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Snell's Notebook Table Of Contents


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INTRODUCTION

I started out to simply try to find the most accurate load for my rifle.  At the time, all of the published information said to just keep trying different powder charges, bullets and primers.  Although I looked in many reloading manuals, and read ever periodical I could find, I was unable to learn of any methodical way to adjust loads to produce accuracy.  I did however find a tremendous amount of non-sense, circular logic, and flowery words without meaning.  As the result, I started to research the topic on the Internet.  Eventually, between some very old periodical articles, and some very new Internet postings, I was able to assemble a fact based logical approach to economic load development of accurate (small group) ammunition.

As the information began to accumulate, I found myself interested in publishing my findings so that the next hand loader could find and benefit from my research.

Of course, many other topics came up, and questions were asked.  So I decided to compile what I know and what I believe to be true into an indexed web page.

What follows is the result.

I have found that a short concise list of safety rules is much easier to teach, learn, and use.

The immortal Col. Jeff Cooper posited four simple rules that I believe are sufficient for all cases.
Rule 1: All guns are loaded at all times.
Rule 2: Never point a gun at anything you don't want to destroy.
Rule 3: Keep your finger off the trigger until you are ready to shoot.
Rule 4: Be certain of your target and beyond.
If you always do these four things you will never be the cause of a shooting accident.

Lets look a little closer at the rules to see how they are applied in daily use.

Rule 1 “All guns are loaded at all times.”

Obviously that can not be true all of the time, but if you TREAT all guns as if they are loaded at all times you will never point a firearm you 'thought was unloaded' at something you didn't want to destroy.

You should never hand another person a gun that you have not personally inspected (cleared), and you should under most conditions open the action, and confirm that the gun is unloaded before you pass control of it to another.

To clear a gun you open the chamber, (where the bullets go to be fired), and inspect the gun to ensure there is no ammunition in the chamber. Further, with regard to repeating arms you should also inspect the magazine, (where the bullets are carried before they are loaded into the chamber), to ensure there are is no ammunition waiting to be loaded.

A cleared gun is one that has been inspected to ensure there is no ammunition loaded or waiting to be loaded.

The exceptions to rule one, that I can think of at the moment are:
These are NOT exceptions:

Rule 2 "Never point a gun at anything you don't want to destroy."

It seems pretty simple. With practice it can be, but without constant vigilance it is very easy to 'cover' ie 'point at' other people in your vicinity. For example if you are hunting, and carrying your rifle in two hands, you must be aware when turning that your muzzle does not 'sweep', 'cover' or 'point at' any person or thing that you don't want to destroy.

Pointing your muzzle up, down, or to the side is acceptable. If your gun should accidentally discharge with the muzzle pointed straight up, your bullet may not have killing power when it returns to earth.

Mythbusters did a very thorough analysis of the subject and found that a bullet fired straight up lost gyroscopic stability near the top of its flight, and then fell to earth sideways. While the returning bullet might hurt if it hit your head, it would not contain sufficient velocity and stability to penetrate deeply. However, if a gun is fired on any angle other than straight up there is a likelihood that the bullet will retain gyroscopic stability and velocity sufficient to case damage or death upon return to earth. The danger range for such is on the order of 3 miles.

If you point your muzzle down and the gun discharges, your bullet may be absorbed by the earth at your feet. (assuming you didn't shoot yourself in the foot), or it may encounter rocks which may cause the bullet to break up and 'splash' in all directions (your legs are closest!). If your gun is pointed some distance away and down, the bullet could ricochet (bounce) and travel miles before loosing lethal energy.

The military has found that on those occasions when carry a loaded weapon inside a vehicle is appropriate, that pointing the muzzle down is generally the best solution. In helicopters and automobiles bullets fired down will do the least damage.

For non-combat applications, keeping your weapon unloaded until just before firing is the best way to ensure that whatever you may point at is not likely to be destroyed.

For combat applications (daily CCW carry, armed response to attackers etc.) you must train often to ensure that your muzzle discipline is as near perfect as possible. This involves training with everyone who may be involved with the operation e.g. family members etc.

If you draw a pistol from its holster or place of concealment you might point it at yourself or others. A right handed shooter drawing from a right side holster using a conventional muzzle down, butt to the rear carry at the hip, will only point his or her muzzle down, then rotate vertically to the target. A shooter using a cross-draw (gun is on the side opposite the firing hand) likely will point the muzzle in an arc that may sweep across any person to the shooter's weak (non-firing) side and/or front. A shooter using a back of the spine holster may point at themselves around the hips and legs, and must make an effort in training to control where the muzzle points, as it is all too easy to raise the muzzle early and sweep yourself on the strong side, or anyone to your stong side. A person using an appendix carry (in front of the hip) is very likely to point the muzzle at their own body during a draw, and must be careful to not sweep to the weak side. A person utilizing off-body carry, for example a purse, typically has the same problem as a shooter using a shoulder holster or a cross draw holster. These are the reasons for Rule 3.

To ensure you are safe drawing your weapon, practice in front of a mirror while drawing slowly and deliberately. Observe the path of the muzzle. As you gain skill, increase your draw speed, and continue to observe the muzzle until you are confidant that no outside force applied during your draw can cause unintended mayhem.

Rule 3 "Keep your finger off the trigger until you are ready to shoot".

As you may have imagined if you followed the discussion about rule 2, there are times when your gun may be pointed somewhere you didn't really want to point it. As long as the guns safety is on, and the trigger can not be pulled inadvertently, there is still a safety margin during these events. Some modern firearms have only one safety mechanism - a small blade within the trigger that only unlocks when a finger (or something like a finger) is pressing on the trigger. Other firearms have additional safety mechanisms. To my knowledge the venerable 1911 semi-automatic pistol has the most at six separate safety mechanisms.

The 1911 Safeties Are:

1. Trigger Disconnector. If the slide is out of battery (pushed back even a fraction of an inch) it is unsafe for the pistol to fire, and the disconnector will disengage the trigger.

2. Grip Safety. There is a panel in the back strap (part of the handle) that is depressed when you grasp the gun with the firing hand. This panel is held open by a spring and until it is depressed the firing mechanism is locked. In other words if the gun is not in a hand it won't go off.

3. Hammer Half-Cock. If the hammer were to fall from any position above a half-cock, without the trigger being pulled, the hammer will catch in a very deep notch and prevent it from hitting the firing pin. Thus a fall on a hard surface, or a snag on the hammer will not allow the gun to fire.

4. Firing Pin Safety. The firing pin is not long enough that it can contact the hammer and the primer at the same time. There is a spring keeping the firing pin away from the primer. When the hammer hits the firing pin it imparts enough inertia to move the firing pin across the gap and hit with enough force to ignite the primer. This is to prevent a fall on a hard surface from firing the gun. Also some (Colt Series 80) 1911's have a firing pin block that prevents the movement of the firing pin unless the trigger is pulled.

5. Thumb Safety. This switch locks the slide forward, prevents the trigger from being pulled, and locks the hammer at full cock. It was originally requested by the US Calvary to provide a mounted soldier the means to make a loaded gun safe to re-holster. By locking the slide forward re-holstering could not force the slide out of battery and prevent the gun from firing the next time it was needed.

6. Trigger Guard. This is the frame extension that surrounds the trigger and is present on nearly every firearm. Its intention is to prevent foreign objects from activating the trigger. You must put your trigger finger inside the trigger guard to pull the trigger.

Modern striker fired pistols based on principles similar to the GLOCK series have these features:

The Glock Style Safeties Are:

1. Trigger Blade. If the trigger blade is not depressed, the trigger can not fire the gun.

2. Trigger disconnector (same as 1911 above).

On some modern pistols there is a 'magazine disconnector' which is designed to prevent the gun from firing if the magazine is removed. The theory is that as a last resort you could eject the magazine before the weapon leaves your control. Perhaps moderately useful during storage to prevent children from activating unsecured guns, while permitting quick action by only inserting a magazine. In most cases a magazine disconnector is a death trap waiting to be sprung on the shooter who has one round in the chamber and is the midst of reloading. That round CAN NOT BE FIRED until the magazine is fully inserted, and MIGHT be fired inadvertently if the trigger is being pulled while the magazine is inserted. Firearms having magazine disconnectors require additional extensive training to avoid all the problems they create.

3. Loaded chamber indicator. This is usually the extractor which is designed so that when a case is present in the chamber it rests proud of the surface. It is always tactile, and sometimes visual.

4. Manual safety. On some striker fired pistols the manufacturer has included a manual safety that typically operates similar to the 1911. When not present, and a DA/SA trigger is in use, the decocker may be present. It's purpose is to relax the main spring by lowering the hammer against a stop that prevents the hammer from reaching the firing pin.

5. Trigger Guard.

Some semi-automatic pistols rely on a heavy and/or long trigger pull to prevent accidental discharge. These are sometimes referred to as DA/SA (Double Action / Single Action) triggers.

DA pistols (as opposed to revolvers) featuring a long heavy first shot trigger pull, followed by much lighter subsequent trigger pulls are not my favorites. The second shot followup is always going off before the sight picture is correct (because the trigger is so much lighter than it was a split second ago), and typically these pistols require a 'decocking' mechanism, to return to a safe (and long heavy trigger pull). I find the decocker to be one of the most 'evil' inventions, right up there with magazine disconnectors! It is just plain wrong to allow a hammer to fall when not either firing, or dry firing. I can not make myself 'believe' in the safety of the mechanism, and I don't like the abrupt stop the hammer experiences because this is the road to fatigued metal. In any case, if you own one of the pistols with this feature (Walther PPK, S&W, etc.) please train yourself and remember all the rules of firearms safety apply at all times, so NEVER EVER operate a decocker with the muzzle pointed in an unsafe direction.  Always get your finger off the trigger and out of the trigger guard before decocking any of these style pistols.

Modern revolver safeties generally consist of the following: Bars that must be moved into position between the hammer and the firing pin by action of the trigger to allow transfer of the hammer energy to the firing pin. Firing pins that do not have the mass to detonate a primer no matter how hard the revolver may fall, and various mechanisms to ensure the alignment of the chamber with the barrel at the moment of firing. They are strong guns with substantial frames made from high strength materials and can withstand much higher operating pressure than older revolvers.

Antique revolvers safeties generally consist of making sure you don't carry a live round in the chamber that is under the hammer. This is accomplished by loading one round, skipping one round, and loading 4 more rounds in sequence, then cocking and lowering the hammer on the empty chamber. Its a skill you should develop early in your training on an antique revolver like the Colt SSA. Failure to abide by the rule to keep an empty chamber will (not may) cause the gun to fire when the hammer is struck. Immediately unload or reload the revolver and make sure the hammer rests on an empty chamber after firing. Simply easing the hammer down, or using the half cock notch will result in undesirable conditions.

Revolvers come in two types, single action, where the hammer is cocked manually for each shot, and double action, where the trigger can be used to cock and fire the revolver in one continuous motion.  Modern double action revolvers invariably possess single action capability in addition.

As you can see, a lot of thought has gone into making guns safe. A safe gun is one that will not discharge inadvertently, but will fire instantly when the operator so chooses. The trigger is the final safety. To defeat the final safety only requires some amount of pull and the gun will fire if it can. If you put your finger into the trigger guard, you have provided a means for external forces (think the side of your holster, or an opponent) to mimic pulling the trigger. Keeping your finger (and everything else) out of the trigger guard area eliminates the threat that the gun can fire due to negligent handling. In particular keep your finger off the trigger AFTER you have ceased firing and MOST ESPECIALLY, keep your finger off the trigger when re-holstering your gun. Train yourself by performing slow draw, aim, fire and re-holster drills. With an unloaded gun, watch what happens if your trigger finger stays in the trigger guard. Some holster designs will cause you to press the trigger. Know your equipment. Always train the way you want to fight.

Rule 4 "Be certain of your target and beyond."

Do not shoot at things you can not positively identify. A very large percentage of accidental shootings happen because the shooter does not take time to positively identify the target before firing. Know you are shooting at the correct target, and conversely know that if you bullet penetrates your target it will not damage anything around or beyond the target. For example if you are hunting and a shot at a great trophy appears on the crest of a hill, you should wait until the animal moves off the crest of the hill, so that a hit or a miss will land where you know the background. Shooting over hills, and across bodies of water, and along or across roads have been responsible for many firearms accidents. There is one time, and only one time when you shouldn't spend too much time worrying about the background, or where your bullet may go, and that is when you are forced to fire on another human. In that one case, most courts have held that any damage resulting from a justified shooting is the fault of the perpetrator rather than the victim. This is the result of the notion that all the results of a bad deed are the fault of the one committing the bad deed. You should of course be aware of your immediate surroundings, and if possible move to ensure you do not shoot into say an adjacent bedroom where you know someone to be sleeping, but in the event your are forced to fire, then fire for effect. The good news is that in your home you can plan ahead to know where safe shooting lanes are located, and you can plan ahead to use equipment and ammunition that is suited for your circumstances.


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MARKSMANSHIP

Marksmanship is the art and science of firing a hand held or shoulder fired gun.

Competition marksmen live in a world of rules.  Their shooting position(s) are dictated by the rules for the discipline or the match.  NRA Smallbore and High Power marksmen have prone, sitting, kneeling and standing positions to master at the same time they skill with their hardware.  Tactical marksmen must master shooting from sometimes difficult positions while being able to utilize a wide range of support options.  Hunters pretty much have no rules about positions, but will find that prone, sitting and standing as well as using whatever support is available are the options.

Beginners would do well to master the conventional match positions of prone, sitting, and standing first.  Then master shooting from a shooting bench, and perhaps last make an effort to use kneeling until you are comfortable and accurate in that position.

Natural Point of Aim - When you have completed getting into position to shoot, close your eyes, relax all of your muscles.  Count to 5.  Open your eyes and check to see where the rifle is pointed.  If it is not pointed directly at the place where you want the bullet to strike, adjust your position and repeat.  Whey you have found your natural point of aim, you should be able to remain in that position for an extended period of time and you should not have to 'muscle' the gun to get onto or stay on the target.

Prone is considered to be the most stable position.  I have found that shooting from a bench is much more stable, repeatable, comfortable, and produces much higher accuracy for most people.  Bench technique is a lot more than just sit down and bang away.  Lets cover some of the basics for each position:

Prone will get you out of the line of incoming fire as much as possible, allow you to sneak up on targets, and crawl around below the top of the brush etc. 

Prone With Sling - In this position the shooter lays flat on their stomach, pelvis and ankles.  Elbows and shoulder support the rifle.  A sling connected to the front of the rifle's stock and wrapped around the 'support side' (opposite of the trigger finger) forearm and upper arm, may or may not be connected to the butt of the rifle.  Properly adjusted the sling will allow the support side hand's grip to control elevation with little effort as it slides back and forth along the forend.  Shooters body should align  just slightly to the support side as viewed from above.   The sling should be tight, and the butt of the rifle should be tight against the shoulder.  Follow through the shot by riding the recoil with the rifle.

Prone with Support - In this position the shooter will be more directly in line with the rifle, and the support side arm will not be involved in supporting the rifle, as it is supported by something (bipod, backpack, etc.).  The support hand can either help control the vertical by supporting the butt, or help stabilize the rifle by ensuring it doesn't fall off the support.  The support hand should be available to make sight corrections (dial up the scope), or adjust parallax (on a modern long range scope).  The support side hand should not in any way support the gun forward of the butt.  Follow through the shot by ensuring the rifle recoils  straight back into your shoulder.  You may support the butt of the rifle with a bag or a mono-pod.

Sitting will get your line of sight above the grass (most of the time), allows you a little bit of lateral (tracking) movement, may offer a position you can remain in for long periods comfortably.

Sitting With Sling - Cross your legs at the ankles, or place your feet slightly apart.  This position changes quite a lot based on foot position choice.  In competition crossing ankles, and leaning far forward so your elbows are outside your knees is typical, and makes this position even more stable for me than prone.  The open sitting position is much more suitable for hunting or tactical applications where movement is necessary. In the 'closed' position the rifle sling is employed the same way as in prone, and the rifle is held tightly to the shoulder.  Follow through by ridding the rifle's recoil.  In the 'open' version of this position, the elbows are placed to force the knees apart.  If you have a spare rope or belt, to constrain the movement of your knees this can be a long term comfortable position.  In the open version of sitting follow through is again a tight sling and riding the rifle's recoil.

Sitting With Support - This position can become difficult if you loose flexibility in your core (eg get fat), because in order for it to work well, you need to lean into the rifle and you don't have the luxury of the rifle's weight, or a sling to help with that movement.  Essentially you will be in a 'kip' position, and muscle strain (bad for shooting accurately) will start immediately.  Generally sitting with sling is more stable, unless terrain offers support for the shooter.  There is also a 'high sitting with support' (long bipod, tripod, shooting sticks etc.) position that may include a short chair, or kneeling with both knees on the ground, while your weight rests on your heels.  Follow though in these supported positions may be best if you utilize 'free recoil' - in other words, your body does not resist the recoil, and does not support the rifle.  When the rifle recoils, it does so free of obstruction (for a few inches).  It does not take much distance between the butt pad and the shoulder to create a free-recoil setup, however in that distance the rifle is free to accelerate and with heavy recoiling calibers that may be enough to cause problems.  In free recoil you firing hand should be setup in such a way that it does not influence recoil.  Many shooters put their thumb on the back of the trigger guard, and their trigger finger on the trigger, and have no other contact with the rifle.  You should work up to free-recoil, its a good way to get a scope cut, drop your rifle, dislocate your shoulder, etc.  Be sure you know what's going to happen.  Heavy (12-13 lb) low recoil rifles (308 Winchester and below) generally have a low enough recoil impulse that free-recoil is practical and you can learn it with little risk.  Don't start off with a 6 lb 7mm Magnum!

Kneeling raises your line of sight above what you had in most sitting positions.  It also allows for rapidly assuming the position, and rapidly resuming stalking, or tactical movement with a minimum of noise and visual signature.  The accuracy potential from kneeling is probably twice to three times better than from standing unsupported (offhand).

Kneeling With Sling - Once again a tight sling can increase your stability significantly in this position.  Your support side foot should be flat on the ground, your shin straight up, your knee bent.  The support side elbow should be just over the knee.  The trigger finger side elbow can be down, but if you shoot a heavy recoiling rifle, putting that elbow parallel to the ground will open your shoulder pocket and allow absorbing much more recoil.  Follow through in kneeling with a sling, as before, to have  tight sling, and ride the rile throughout the recoil pulse.

Kneeling With Support - Generally this position only happens if you have to work from under some obstruction.  Typically any shot you would take from this position can just as easily be taken from standing with support, and with about the same accuracy.

Standing, also known as 'offhand' is the most challenging position to shoot accurately from.  In this position a sling is generally a detriment to accuracy.  Since most hunting and tactical rifles will have a sling attached part of your training for this position will be to secure the sling so that it does not impart movement.

Standing Unsupported - In this position you will not be able to hold your sight picture for any more than a few seconds.  There are at least two ways to address this problem with technique.  First what I call the 'shotgun approach' which works well for quick shots on larger targets.  Mount the rifle so that the sights are in the correct position instantly.  Your eyes should be looking at and focused on the target as you mount the rifle.  The moment the rifle is mounted, you should be able to pickup the sights.  If you try to stand still you will wobble around in circles (we'll talk about that next).  To keep from wobbling around you will need to muscle your gun in such a way that the sight track across the aiming point (AP).  If you move too quickly this won't work as well as if you move slowly and deliberately.  The amount of movement is very small, maybe not more than 2-3 MOA (Minutes Of Angle).  As you push your sights across the AP coordinate your trigger finger to break the shot just before your sights reach perfect alignment.  This movement is very similar to the way a shotgun is fired.  It takes practice to achieve high accuracy, but once you get the hang of it, you can take on difficult targets at high speed, with a great deal of success.  The reason it works, has to do with how your muscles don't want to hold still as much as they want to move.  You can apply a very smooth movement across the target, but you can't hold very still on target.

Standing Supported - In this position you will be erect behind shooting sticks, tripod, or rested against a support (tree, door frame etc.). Your rifle will be constrained at the point where the support occurs.  If you choose to put the support near the balance point of the rifle, it will be easy for you to move up and down.  If you put the support nearer the muzzle, you will have to make gross movements to change your point of aim, and those movements will by necessity be made by your entire body, or by repositioning the support.  This position will feel very un-natural until you have practiced it a lot.  It will also take quite a while for you to determine the correct length for adjustable legs, and position (fore and aft) on the rifle.  One trick to really 'clean up' this position is to back into a tree or other stable support.  You won't believe how much your upper body wants to move around until you constrain that movement.  In standing supported you may find the sights are wandering all over the place just like standing unsupported, but if you watch closely, you'll see that they tend to oscillate in a typically circular pattern.  By watching the pattern, you can predict when the sights will approach the AP.  If you have excellent trigger control, you would take up 3/4 of the trigger weight as soon as your sights are close to the AP.  Hold that.  When your sights come around on their oscillation, take some of the remainder as the sights approach the AP, and hold as the sights depart.  Continue this until you have what Col. Jeff Cooper called a 'surprise break'.    This trigger technique is valid for all positions, at all times, but you will get the best training opportunity in Standing Supported.

A word about follow through; The ideal situation is for you to have zero reaction with the shot breaks.  Be like a bag of sand, just absorb the recoil, hold the trigger, and DO NOT BLINK.  That last one is perhaps the single hardest thing to do for most people.  You will have to convince your subconscious first to delay the blink, then since 'nothing ever happens' to do away with the blink completely.  Blinking is a reaction to an unexpected event typically recoil, or sound, or for scoped rifles, the loss of sight picture.  Blinking will prevent you from seeing where your shot impacted, which will prevent you from making a correction if necessary.  One technique I've used to overcome blinking is to become so engrossed in watching the scene unfold after a shot, pickup the trace, see the 'glint' from the bullet, watch for impact, etc.  that I actually don't blink.  It takes a while (unless you shoot tracers - that's a real shortcut!) until you can stall the blink response long enough to see anything of interest, then all of a sudden you will 'get over it' and be able to watch everything.  Once you have that mastered, you can work on getting recoil to push your rifle straight back, and returning the rifle to 'battery' all during bullet flight time.  If you want to work up in stages, I recommend you start by learning to hold your trigger all the way through the shot. 


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FUNDAMENTALS OF MARKSMANSHIP

You will hear instructors mention 'The Fundamentals Of Marksmanship' very often.  Mastery of the fundamentals is key to shooting accurately.  So what are these fundamentals?

According to the US Army these are four fundamentals of Marksmanship:

  1. Steady Position
  2. Aiming
  3. Breath Control
  4. Trigger Squeeze

This is a link to the US Army Study Guide

The Washington State Criminal Justice Training Commission Patrol Rifle Course added the following:

  1. Grip
  2. Stance
  3. Breathing
  4. Sight Alignment
  5. Sight Picture
  6. Trigger Manipulation
  7. Follow Through

This is a link to the document

Another US Army guide is much more simple:

  1. Properly point the rifle at the target
  2. Fire the rifle without moving it

This is a link to the web page, there are some very good graphics on this one.

To pre-load a bipod; as the last step in building your natural point of aim shooting position, press your shoulder forward just enough to rock the bipod to it's forward limit of travel (which may be very small).  Don't press hard enough to skid the feet.  Ideally, at the moment of recoil, the bipod will rotate backward, and your shoulder will stop the recoil motion before the bipod feet skid in recoil.  The idea is to enable the bipod to have the range of motion necessary to allow the rifle to recoil without the bipod feet moving.

Classic Positions

Eye Dominance

Most of us are born with an innate desire to use one eye or the other to 'see' things.  Assuming you start out as a youngster with equal eyes, you probably will develop a dominance in the eye on the same side as your 'handedness' eg; right handed and right eye dominant.  If one eye is stronger it may become the dominant eye even though it is on the opposite side eg; right handed and left eye dominant.  It is possible (and desirable) to at least be able to switch eyes with the hand that's doing the work.  In the shooting world, this would manifest as being comfortable switching the eye you sight with when you switch the hand holding the firearm.  Where rifles are concerned, it is extremely desirable to achieve the ability to be ambidextrous with both your hands and your eyes because of the way the rifle stock naturally places the sighting plane in line with the eye on the side where the rifle is being shouldered.  There are any number of practical reasons to train yourself, and those you train, to be able to shoot proficiently from either shoulder.  The same is true for handguns, however because there generally is no stock to shoulder fixed relationship it is possible to simply move the gun into line with the dominant eye. 

Determining Which Eye Is Dominant

There are several techniques that work.  The following is one quick and simple way to show a shooter his or her dominant eye:

Place your hands together at full extension with your index fingers and thumbs forming an opening. 
Make the opening as small as practical, say 2-3 times larger than the target, and use your hands to block out as much of the rest as possible.
Look through the opening at a distant (10 foot or so) target.  It is important that the target be at least 10 feet to get this right.
While keeping your concentration on the target, and your hands in the same position, slowly bring the opening toward your face. 

As the opening gets closer to your face it will tend to center up on the eye you are using.  This indicates the dominant eye because no effort was made to choose an eye in the beginning.

The Dominant Eye Finger Drill

Once you understand that the image you see is the composite of the images generated in both eyes (binocular vision), you will begin to understand how to mentally select the eye you desire to use.

Another drill that my father was taught in the Army in the 1920's uses just your index finger (either hand) held up like a front sight at arms length.  Again the target must be at least 10 feet (or more) distant for this to work.

Look at the target.  Focus on the target.  Hold the tip of your finger just under the target (don't look at your finger, keep looking at the target).  While you are looking at and focusing on the target, you should see two fingers, and both should be out of focus and appear semi-transparent.  Each eye sees the finger from a different perspective, your brain puts the image of the target together in a single plane, and your finger(s) are in the foreground out of focus.

Here comes the fun part.  While continuing to focus on the target pick one of the finger images and place it under the target.  If you chose the left image, you are right eye dominant, if you chose the right image you are left eye dominant.  Without changing anything else, close your right eye.  Did the finger continue to be under the target?  If it did, you are using your left eye, and the right image of your finger.  If you open both eyes, then close the left eye you should see your finger jump out from under the target.  If you happened to do it the opposite way, just reverse everything I just said.

The very useful part of the finger drill is that you can very quickly learn to move your 'chosen' eye from side to side, and you will learn what it feels like to choose an eye, and rapidly you will develop the ability to use either eye as your dominant eye.

If you are training someone in the finger technique, you use your (pick one) eye as their target, and run them through the close eye, switch eye, then to graduate with both eyes open consciously pick which eye to use.  As the target, you will see the student's finger tip move back and forth between their eyes as they run the drill.  If the student's finger gets stuck on their nose, try making the distance a little greater, or go back to explaining what a sight picture looks like.

If you have never tried an eye dominance drill like this one, I recommend you do so right this minute.  Did you feel it 'pull' on your eye when you swapped dominance?  That is like doing your first push up.  Keep at it and you will be able to do it with ease.

When I get a few more minutes I'll try to sketch up this drill so you can see better what I am talking about, or just contact me if you have any questions.

Sight Alignment

As firearms technology progressed, it became apparent that a system was necessary to help the shooter point the gun at the target. Shotguns were found to work well with small bright beads, while rifles and pistols being that they fired single bullets, needed something more precise.

There are a number of variations on the front and rear sights that have been found useful over the years. Their purpose is always to align the barrel so that the bullet impacts where desired. Bullets do not travel in straight lines, and so sights for precise and long range work differ considerably from sights for short range fast work.

In this document, I am only going to cover rifles, and long range, so we will keep the discussion of sights confined to those useful for that purpose.

Breath Control

Heartbeat Control

Trigger Control

Follow Through

The Don'ts

After The Shot

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DOPE - THE LOG BOOK

DOPE is what shooters have been calling their 'Data On Previous Engagements' since the early 1900's.  It is a formalized method of recording critical information about each shot, with the goal of eventually providing sufficient information that the shooter can achieve first round hits on targets at extreme ranges under extreme conditions.  Shooters keep a DOPE book for each rifle.  Within the book there are sections for recording the data about the rifle, about the ammunition, about the target(s), and about each shot fired.

By categorizing, compartmentalizing, standardizing an recording information about each shot we take, we can build a reference work from with it is possible to gather, keep and use information we would otherwise loose. This information is valuable in allowing us to make corrections based on previous similar engagements and to allow us to modify our corrections based on changing conditions. We also gain a better memory of things like the number of shots fired through a barrel, and the effect various physical parameters have on our shooting. The DOPE book also contains charts and other reference material we may use to arrive at a firing solution.

NOTE: Even though there are many very good and accurate exterior ballistics programs available and even embedded into some of our environmental measuring equipment, keeping a DOPE book will have benefits as your memory of events, settings, conditions fades with time. The DOPE book is a journal designed to record both the technical data and the shooters observations.

Environmental

Sky & Light


Cloud Cover

Quality of Light

Direction of Light

Light, particularly coming from low angles, or from directly overhead, distorts shadows that your brain has been trained to use in recognizing the scene your eyes are viewing.
Light coming directly toward you can blind you to what lies in the smallest of shadows.
Particularly with iron sights, but still applicable to telescopic sights the view of your aiming point varies under extreme lighting conditions, and point of impact may change in a predictable way as the result.  Logging the direction of illumination will help you re-create a scene for training, and will help you avoid previous errors.

        See “Primer Output and Initial Projectile Motion

NOTE: For Aberdeen Proving Ground Research follow these links:
Flame-Spreading Process in a Small-Caliber Gun
Primer Output and Initial Projectile Motion
High Speed Measurement of Firearm Primer Blast Waves
In-Chamber Primer Force and Case Pressure Measurements of the 5.56-mm Cartridge
US Army RDECOM Research Laboratory Technical Report Search Page

NOTE: This may happen too: When the pressure is sufficient to overcome bullet inertia, the case mouth has already been inflated and is pressed out to the limits of the chamber.  At this point there is no support for the back of the bullet, and the bullet is typically moving at less than 20fps.  Until the ogive is fully engraved into the rifling gas will escape around the bullet at 30-40K fps.  A very violent and potentially turbulent environment in the chamber throat.  According to Aberdeen Proving Ground as pressure rises during bullet engraving, surprisingly,  there is no significant difference in pressure curves between a rifled barrel, and a smooth bore barrel.

From the above, you can conclude that adjusting seating depth may have more to do with controlling the initial shape of the pressure curve than anything else.

Long bearing surfaces, absolute bullet concentricity, and minimum slop in the case to chamber are critical.  And that is assuming you use a match grade bullet having its center of gravity congruent with its center of rotation.

NOTE: This may also be happening: My best guess has to do with the subtle variations in pressure vs time during the time between shot start and (for example), when the rifling is engraved.  During this period the available volume is increasing as is the pressure.  By increasing the charge weight, the initial volume decreases as does the available volume at the point of engraving.  Powder burning characteristics (Ba or Burning Rate in particular) change as a function of pressure, thus at some point in the charge weight variation tested, the burning rate changes inversely to the charge weight enough to produce similar pressures for a several tenths grain charge change. 

NOTE: This graph was published by Aberdeen Research Lab in 2016 showing the position vs time for M855 (55 grain 5.56 NATO) and M856 (55 grain 5.56 NATO Tracer) bullets during the first 450 nano seconds after firing. Note that the bullet passes through contact with the rifling and engraving with no discernible variation in the rate of position change or measured force.

NOTE: A mili second: 0.001 Sec is 1/1,000 (1 thousandth) of a second.
A micro second: 0.000001 Sec is 1/1,000,000 (1 millionth) of a second.

Position - Time plot

NOTE: This graph was published by Aberdeen Research Lab in 2016 showing the acceleration and velocity of a 5.56 NATO M855 bullet during the first 400 nano seconds after firing. Primer induced velocity reaches to about 0.17 mS where acceleration from propellant burning begins to takes over.

NOTE: At 0.0004 seconds the M855 projectile has traveled 0.75" down the bore, it is traveling (in that instant) 156.25 fps.

Prime imparted velocity

NOTE: Read the complete report by Aberdeen Research Lab: Primer Output and Initial Projectile Motion.

NOTE: The transition zone between primer induced velocity and powder induced velocity is likely the area affected by varying the seating depth of the bullet.

In our search for the ideal load we are looking for consistent muzzle velocity and consistent group size. Once a case, primer, bullet, powder charge has been decided upon the only parameter available to change is the bullet seating depth. Varying the seating depth changes the available initial volume, which no doubt changes the point on this chart where bullet velocity and the resulting increase in available volume, are governed by gas generation.

NOTE: When you set your resizing die you are controlling the relationship between the case and the chamber. You must be careful to ensure that the CBTD (Case Base To Datum) dimension is within the SAAMI Headspace dimensions.

NOTE: One major goal of accurate ammunition manufacturing is to ensure the bullet is concentric to the center of the bore at the moment of firing.

As the case shoulder is bumped further toward the case head, the cartridge looses a bearing surface upon which to elevate the bullet into line with the bore.

Extractors generally are on the side of the bolt, and do not exert much upward influence on the cartridge case, so as support at the front is removed, the case tends to lay in the bottom of the chamber. Do not assume the case neck can support the case as the chamber is several thousandths larger in diameter in that area to allow bullet release.

Seating the bullet to a zero jump length or longer will force the case into better alignment, but may also cause the bullet to stick in the bore if the case is extracted prior to firing.

The ideal situation is to have the cartridge case shoulder in tight or not more than 0.002" loose contact with the chamber while the case head is flush on the bolt face prior to firing.

NOTE: The air in the barrel at the instant of firing is compressed by the escaping gas and the accelerating bullet and creates an initial gas jet that has some potential to disturb the point the barrel is aimed to, however the more important effect this gas jet can be used for is to penetrate and remove any muzzle cover (electricians tape) that may be applied to a hunting rifle to keep foreign debris out of the muzzle. The escaping air will easily remove the muzzle cover with no effect on the shot.

From this point onward the bullet is no longer under the influence of the shooter or the rifle. Characteristics in this region are referred to as Exterior Ballistics. For a thorough treatment of the behavior of bullets in this region please refer to the collected works of Brian Litz.


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BARREL MOVEMENT

To visualize barrel dynamics, first remember that steel is elastic (in the sense that it stretches and bends), then imagine a very slow motion view of your rifle barrel during the sequence of firing. I'm going to try to paint a picture of words that explain each of several motions that occur in a barrel when it is fired. Once you 'see' what I'm talking about move on to the next description and add that motion to your mental image.

Just prior to firing, the barrel is positioned horizontally, and the muzzle is drooping a very small amount due to gravity. Thus, initially the muzzle is pointing below the centerline of the barrel. This type of structure is know as a 'cantilevered beam'.

See the previous section on Internal Physics for the details, at this point in the discussion lets simplify to the following:

The firing pin hits the primer, the primer detonates, the primer flame lights the smokeless powder which burns ever more rapidly as the gas it generates is confined by the cartridge, bullet, chamber, bolt, and barrel. Pressure inside the cartridge increases very rapidly to drive the bullet out of the cartridge case. The forward motion of the bullet creates an equal and opposite recoil force. Lets call this the axial motion.

Recoil starts the barrel moving backward, the recoil force is translated through the recoil lug to the stock, where the shape of the stock typically causes the muzzle to rapidly move upward.

Remember how the muzzle was drooping below the centerline of the barrel? Now, as the barrel starts to move upward the muzzle lags the centerline of the barrel until the stiffness of the barrel forces the muzzle to bend upward, overtaking the centerline until the muzzle reaches some displacement above the centerline where barrel stiffness causes the muzzle to start bending downward with respect to the (moving) centerline of the barrel. This is the 1st Mode of deformation of the barrel. There are many others, but this on is of primary concern to us with regard to developing a load that shoots with minimum dispersion.

In a particular 308 Winchester load with a 175 grain bullet, fired from a 26 inch 1:10 twist barrel, the maximum internal pressure of 55,338 psi is achieved at about 0.360 mSec when the bullet is only 1.24 inches down the barrel and is moving about 846 feet per second. By the time the bullet is 12 inches down the barrel the pressure has dropped to about 15,000 psi, and the bullet has accelerated to about 2294 feet per second. Just as the bullet exits the 26” barrel it has reached 2691 feet per second, and 93,752 revolutions per minute. The pressure has dropped to about 6,727 psi, 1.329 mSec (0.001329 Seconds) have elapsed.

The barrel is elastic so it winds up some amount while the bullet is in the barrel. Lets call this a torque vibration. We will never see the torque vibration by its self, but when added to the vertical vibration it creates a small horizontal component we will call the horizontal motion.

In addition to all that, the sound of the firing pin, the explosion of the primer, and the rapid expansion of the smokeless powder gas causes the barrel diameter to expand.

NOTE: This is the OBT (Optimum Barrel Time) theory's main component.

The largest component of this motion starts in the center of the chamber, and travels down the barrel to the muzzle at the speed of sound in steel, about 16,000 fps. Once the radial expansion reaches the muzzle it reflects nearly perfectly back toward the bolt face, but is distorted when it encounters the barrel threads, recoil lug, and uneven thicknesses of the action. The radial expansion is called a 'shock wave', and it bounces back and forth between the ends of the barrel causing the muzzle diameter to expand when the wave is present at the muzzle. The muzzle returns to its nominal diameter when the wave is at the receiver end of the system. Thanks to Chris Long http://www.the-long-family.com the author of “The Shockwave Theory”, we have a very good idea when the 'quiet' nodes occur for a given barrel length. http://www.the-long-family.com/OBT%20Table.pdf During the 1.329 milliseconds that it takes my 308 Winchester 175 grain example to exit the 26 inch barrel, the shock wave has been to the muzzle and back to the receiver 5 times. In this example the shock wave is at the receiver just when the bullet exits the barrel. Lets call this a radial motion.

Varmint Al has graciously permitted me to include some of his engineering simulations to illustrate what is occurring.

Refer to "Full 3D Finite Element Analysis of a barrel's first few modes shapes and frequencies calculated with the LS-DYNA code."

While the information on this page may be a bit technical for some, the takeaway information is that the largest and most important deformation of the barrel (with respect to where the muzzle is pointing at bullet exit) is the vertical Mode 1 Cantilever Bending motion.


Now refer to "Varmint Al's Barrel Tuner Analysis ..." The first chart "Typical Muzzle Projection Curve" shows a graph of the Mode1 deformation (Muzzle's Projection to 100 yard Target in Inches) versus time.

Muzzle Projection Curve
Remember that we are starting out with the barrel drooping slightly due to gravity, at the shot start recoil and stock shape combine to cause the muzzle to bend downward then upward. Thus the Muzzle Projection To 100 Yards numbers start at about -0.68 (about 11/16" low) and move upward to about -0.06 (about 1/16" low). This effect begins at about 0.0006 Seconds and peaks at about 0.0011 Seconds. Bullets exiting the barrel during the barrels upswing (0.00075 - 0.00110 seconds) will tend to impact on the target closer together than bullets exiting the barrel after the motion reverses (0.00110 - 0.00120 seconds) because the bullets with faster muzzle velocities exit sooner and are pointed lower than slower bullets which are pointed higher. In other words the vertical barrel motion tends to cancel out muzzle velocity variations in this region. The inverse is true after the barrel reverses motion, causing much larger groups.

There are a couple of ways to cause the bullet to exit before the peak of barrel deformation, but the one we are going to focus on is changing the velocity of the bullet by changing the powder charge. This is called a Ladder Test or more precisely an Audette Ladder Test.

Al explores the effect of barrel motion on vertical dispersion by simulating a ladder test (increasing muzzle velocity by 25 fps per shot) then zooming in on the peak range of barrel motion and plotting shots against their 100 yard impact points in this chart, which pretty much says it all.

Muzzle Projection for the Ladder

The barrel starts out sagging due to gravity.

Recoil and barrel deformation cause the muzzle to point downward slightly, then upward by nearly 3/4" projected to 100 yds by 0.001 seconds from shot start.

Muzzle Vertical Velocity
On this chart, positive vertical velocity is downward, negative vertical velocity is upward (against gravity).


The barrel has no vertical velocity before the shot.

At shot start the barrel moves downward  at a rate approaching 1.5 inches per second then reverses to achieve between -1/2 and -2.5 inches per second upward velocity during bullet exit window for the shots of the ladder test.

This vertical velocity is retained by the bullet after exit.

Muzzle Projection At Bullet Exit Times
Each shot has a different velocity by 25 fps. Each exit time is plotted on the Muzzle Pointing Curve (MPC). By taking the vertical axis value for each shot a virtual ladder test is performed.

NOTE: A key takeaway here, it to realize that the major muzzle movements (vibration) are identical for each shot, without regard to muzzle velocity, and that there are some very minor vibrations that are sensitive to muzzle velocity which only account for extremely small variations in the muzzle pointing position at a given moment in time for each shot.  The wave shapes in this region of the chart are similar in frequency, and differ mostly in amplitude.  Also note that the total variation in muzzle velocity is 350 fps in this example.


Ladder Test
Varmint Al says:

LADDER TEST RESULTS.... The total vertical spread with the bare barrel is 0.5539 inches compared to 0.2097 inches for the case with the tuner and the weight forward. The chart represents where the bullets would strike at a virtual 100 yard target for the range of velocities listed. For Esten's Rifle with no tuner, there are three groupings near 3475 fps, 3375 fps, and 3275 fps. These muzzle velocities could be loads where the rifle is "in tune". The yellow circle (3475 fps) is under the gray green circle.

We are mostly interested in the bare barrel results because most of us are probably loading for hunting or tactical shooting, and won't have a barrel tuner.

The shot clustering Al refers to is exactly what the Audette Ladder Test is designed to reveal, without needing a computer to figure it out.

The small vertical variation at 100 yards is the reason we want to do the Audette Ladder Test at longer ranges so as to amplify the effect. The down side of using longer ranges for ladder tests are that wind can have a significant effect on the horizontal component (which we should ignore), and a minor effect on the vertical component which may be pretty small to begin with. The best time to do Audette Ladder Tests is in very calm wind condition, with as little cross wind as possible.

You must be able to accurately label the bullet impact and the charge that created it. If you have target butts where an assistant can pull the target down, record the shot, and put it back up, then the longest range you have is what you should use. If you don't have that luxury, and your spotting scope runs out of resolution before the distance you want to use, consider a camera system, or else you'll have to approach the target between each shot to log it. Don't assume the ladder will be an incrementally ascending or descending string of shots, as that just about never happens.

The Celestron C90 MAK telescope with the appropriate erector and eyepieces can resolve bullet holes to just about the maximum distance the current mirage conditions will allow - generally 30 cal to about 300 yds. This spotting scope is quite inexpensive compared to the typical shooting spotting scope, and is quite a bit more fragile.

You can color your bullets with a permanent colored marker, and some of that color will rub off on the target paper as the bullet travels through it. For cases where the bullets impact a little apart from each other, this technique (which might take a little time to perfect), is the fastest, easiest, and least expensive way to get the 'which bullet made which hole' information.

Some people have suggested that a ladder test should be a group fired with each charge increment. If you do this, you'll need to fire enough shots to burn your barrel out before you are done, and unless each shot in the group has nearly the same muzzle velocity you'll need to fire enough at each charge increment to get a valid statistical sample to determine where the center of the group is (not the group size). Each shot in the ladder test tells its own story quite accurately. There are a number of actions you can take to improve your group size once you figure out your powder charge

With all that in mind, Varmint Al has this to say:

Comparing 100 and 600 yards

LONG RANGE TUNE.... Here is an interesting set of trajectory plots. No matter how carefully one loads his ammo, there are going to be small differences in muzzle velocity. Consider a load with an average muzzle velocity of 2915 fps with a muzzle velocity variation of 15 fps. Then consider this load tuned for zero vertical at 100 yards that overcomes that small difference in muzzle velocity.

This same load will be out of tune by 73.23-71.50=1.73 inches of vertical at 600 yards. However if the load is tuned so that there is 12.21-11.92=0.29 inches of vertical at 100 yards (with the slower muzzle velocity hitting higher) then there would be zero vertical at 600 yards. This chart is for a 6.5mm 140 gr VLD bullet with a 0.64 BC. A similar chart or table can be made for each long range load. If you are in tune for zero vertical at 100 yards, you will not be in tune for zero vertical at 600 or1000 yards.

NOTE: One important take away is "slower hits higher". If slower bullets hit higher its because they were in the barrel longer, during which time, the barrel pointed higher, plus the barrel's vertical motion imparted a larger vertical velocity component to the slower bullet. These are all indicators that your load is on the 'correct' side of the vertical Mode 1 Cantilever Bending motion.

I think another way of saying this is that you should do ladder tests at long ranges. In terms of curve fitting, if you have lower vertical dispersion at longer distances, the vertical dispersion increase at shorter distances is smaller than if you set it up the other way around.

One more point to consider; when setting up your ladder test, keep in mind your ultimate target. If you are a hunter in particular, what is the longest range you will allow yourself to take a shot at a game animal? What is the size of the animals vital zone? How large is one click on your scope when projected to that range? If you can get your vertical dispersion inside one click at your max range you really only have to worry about accounting for wind where the bullet travels to the target.

In summary; while the bullet is inside the barrel, the barrel moves vertically, horizontally, axially and radially with respect to the initial centerline of the barrel. Regardless the velocity, the barrel moves substantially identically between shots. Since each shot has a slightly different velocity, getting the bullet to exit the muzzle when the muzzle is nearing it's peak upward position is the secret to achieving accuracy. Using a ladder test to map the barrels motion versus muzzle velocity over a small range of change will paint a picture from which it is fairly easy to select a powder charge that will cause your bullets to have little vertical dispersion. You only need, and should only use, one shot per charge weight at this stage of development. To use more shots at a given charge tends to confuse more than anything else. Ideally, you must know the following about each shot:

Now that we have an appreciation of barrel movement during the shot, we need to address a couple of other topics before we move on.

Satterlee 10 Shot Ladder Test

Right about here, a lot of you may be wondering about Scott Satterlee's 10 shot Load Development Ladder Test.  Scott noticed that there is a velocity change plateau in the typical incremental charge ladder test, and that the lowest velocity variation load occurs in the middle of this plateau.

I have not been able to find any theory, finite element analysis, or simulation that explains why this plateau occurs, but occur it does, and it can be used to quickly choose a correct powder charge for an accurate long range load.

There are a number of videos, and much internet discussion of how to perform Scott's test.  Here's a link to the 6.5 Guys interview with Scott Satterlee  on the subject.  One observation that Scott makes and I agree with is that once a velocity has been identified for a given rifle, case, primer, bullet, the powder can be changed, and as long as the powder charge achieves the same velocity, it will be an accurate load.  I believe this is a demonstration of all of the barrel movement observations detailed above.  Due to the variations in burning rate and total energy of each powder, I believe there are a limited number of powers that will demonstrate suitability over the entire range of use.  For example, a faster powder may, when the correct velocity is found, only fill the case to 75%, and because it has such a large open space within the case, it may not ignite the same way every time, and thus have an unusably large velocity spread.  Ancient wisdom tells us that the best loads occur at above 90% fill ratio, with the slowest powder that will achieve the desired velocity.

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AMMUNITION DYNAMICS

Ammunition must fit the chamber for best accuracy.

Simply 'being in the chamber' is not fitting into the chamber. To fit, a loaded round must be very close to all of the dimensions of the chamber, so that the center line of the bullet is positioned as close as possible to, and parallel with the center line of the barrel. The bullet must travel down the barrel with its center of rotation very close to its center of mass.

When a virgin or full length resized case is chambered, there is typically a significant amount of slop in the length and diameter of the case.  Case misalignment in the chamber can destroy any benefit of bullet to case concentricity.

When a new case is fired it expands under tremendous pressure to fit very tightly into the chamber machined into the barrel. As the temperature of the case returns to normal, the case (because it's brass) contracts very slightly in diameter and length. The fired case is now as close to the chamber's dimensions as it can be. Try not to mess that up! Correct neck sizing alone is sufficient to reload this piece of brass, and if it is done with a conventional die, ensure (by measuring before and after) that the neck expander does not alter the headspace, or diminish concentricity. Hand dies are the best because they don't ever pull the case from the neck, and they are small, accurate, concentric, fully support the case, and easy to use anywhere.

Measurements

In order to manufacture accurate, and consistent ammunition, you need to know some characteristics of the ammunition.  We measure and record the following information for reference, and to inform our adjustments.

CASE BASE TO BULLET OGIVE (CBTO)

LOADED NECK DIAMETER

Do not let this dimension get to within 0.001" of the FIRED NECK DIAMETER or you may experience a pressure event.

BULLET BEARING LENGTH

The barrel first has a hole of 'BORE' dimension drilled through its length.  Next a 'rifling tool' cuts 'rifling' groves into the bore.  The groove diameter is typically used as the caliber designation of bullet diameter.  The bore diameter however is the dimension of the point of first contact between the bullet and the rifling.  Typically the breach end of the bore is chamfered.  The exact point of first contact between the bullet and the bore was established when you measured CBTO.  The shape of many bullets provide a curved contour from the bullet datum line (point of contact with the bore diameter) to the maximum diameter of the bullet, and on to the point at the base of the bullet where its diameter is less than the bore.  Some bullets shape in this area is a cylinder with straight sides.  The bullet receives its stabilizing spin force by being engraved by the 'lands' (remaining surface of the original bore diameter).  The strength of the bullet material being so engraved to a large degree determines the maximum twist rate for the bullet.  The length of the bullet subject to engraving affects the ability of the bullet to align concentric to the bore, and affects the net resistance to movement (friction) each bullet presents.

Bullet to bullet variations in bearing length affect muzzle velocity by changing the rate of change in the combustion chamber size as the bullet move into the barrel and thereafter until the bullet exits.

To measure bullet bearing surface, equip your Hornady Bullet Comparator with two Ogive inserts of the correct datum (bore) size.  Measure the distance from the bullet tip ojive to the bullet base ojive (on the boat tail typically).  Sort bullets by this dimension.
Brass becomes brittle from work hardening, meaning that every time brass is compressed or stretched, the crystalline structure becomes more organized.  To make brass more compliant and return the crystalline structure to a more random state, heat must be applied.  The amount of heat, and the duration of the heating work together to achieve the effect called annealing. The only part of the case which benefits from annealing by the handloader is the case neck, which is also the part which received the greatest amount of stretching and compressing during the firing-resizing-loading cycle.  The base of the case has much thicker walls to help contain the high pressure experienced during firing, and has been correctly hardened at the factory.  The shoulder of the case is not critical for hardness, but does offer a visual reference of the annealing as the heating usually causes a color change which will be visible in this area.

Handloaders can now purchase case annealing rigs from several manufacturers, some use induction heating, and others use propane torches.  The manufacturers generally go to the trouble and expense to accurately heat a lot of cases and record settings for their machines to duplicate their results.  

It is possible to adequately anneal cases by hand with nothing more than a dim room, power screwdriver, deep well socket and a propane torch. 

The benefit of annealing is that neck tension will become very uniform, leading to uniform initial conditions at firing, and cases will achieve remarkable longevity in service.  Accuracy is the goal, and annealing directly contributes significantly to improved accuracy.

I encourage you to research the topic online, and don't be afraid to try annealing for yourself.


Annealing Setup 1Annealing 2
Here's my cheap battery powered screwdriver with a deep 12mm socket and my propane torch with gold pan used to catch hot brass.
Two Annealed Two Fired Cases

Measuring Tools



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Mounting a Tactical Rifle Scope

Bryan Litz of Applied Ballistics has made both a video and a document covering the Tall Target Test.  You should start by reviewing both.

When you mount a tactical scope on a precision rifle, you expect to be able to make sighting corrections that accurately place your rounds on target at long range.  Here are the steps to ensure you have correctly performed the work:

Select a mount - precision rifles typically use MIL-STD-1913 or 'Picatinny' rail.  Such rails come in various configurations providing from zero (0) to at least 30 MOA (Minutes of Angle) slope to enable scope adjustment for long distance shooting.  Typically 20 MOA is sufficient for most sporting calibers, while 30 MOA is typically reserved for large calibers and extreme long range.

Select a scope - tactical scopes have easily adjusted elevation and windage knobs, and probably will have a parallax adjustment.  1 inch (25mm) scopes have less vertical adjustment range than 30mm or 35mm tube scope.

Select a level that mounts to your scope body.  Levels that attach to your rifle only tell you the rifle is level, and are not appropriate for precision rifles because they can not be ajusted to match the scope reticle.

Select your scope rings.

Install your rings and scope.

Tall Target Test

Review the Tall Target Test video and document

NOTE: The Tall Target Test can be performed while you are breaking in a new rifle barrel.  Read Rifle Cleaning Protocol

Assemble a target with sufficient height to contain both the aiming point and a bullet fired with the maximum vertical elevation your scope can produce from the aiming point.

NOTE: Scope manufacturers list the total elevation adjustment, it is up to you to mount your scope in such a way as to maximize the use of that range.  For long range shooting, typically a 20 MOA rail is used to tip the front of the scope down by 20 Minutes of Arc, moving your 100 yard zero to the lower 1/3 of the scope adjustment range, and maximizing the available upward adjustment.  For example, the Vortex HS LR 6-24x50 FFP XLR moa scope has a total of 65 MOA vertical adjustment, and 40 MOA of total windage adjustment.  From the factory, the scope is set at the mid point where there is about 32 MOA up and 32 MOA down, 20 MOA left, and 20 MOA right.  When placed on a 20 MOA rail and zeroed (if all else is in alignment) there will then be about 52 MOA up, 12 MOA down, and still have 20 MOA each left and right.

If your scope has 30 MOA up adjustment you'll need a target about 36" tall, for the 52 MOA in the example above, a 4' target is too small, and going all the way to an 6' target is probably the easiest as 54.4" will be required if everything is working correctly, perhaps more if not.

Your target needs to have enough room below the bottom and above the top to capture any groups or shots that are misplaced, probably 6"-12" is sufficient.

Your tall target should be placed on a backer that has a true straight edge, and that edge should be dead vertical as measured by a long construction level.  The line down the middle of the tall target should also be measured vertical.

Before you zero your rifle and complete your scope installation, you have one adjustment remaining, calibrating the elevation control to the fall of gravity.

You will need a regular target to establish zero.


NOTE: If your group develops off the vertical line, you may need to make a minor correction to the scope rotation and repeat the test.  Do this before you continue, and be sure to adjust your level to the new rotation.

There are a couple of additional tests you can do while you have this setup in place.

Keep the record of your Tall Target Test in your DOPE book.  Well documented pictures are useful too.

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Laser Range Finder Calibration & Confidance Testing

Beginning Development 01/12/2019 -- NRFP

For long range accuracy it is critical to know the true range to your target.   As the bullet travels away from the muzzle it slows down due to drag, by the time it is 500 yards or more down range it has begun to reach the zone where its vertical motion (fall due to gravity) is beginning to affect its ability to hit within 'x' inches of where it was pointed.  From here on the bullet only falls faster (32 feet for every second of travel times every second of travel).  So instead of a 'flat' trajectory, we begin to see an arc and as distance increases the angle of the arc becomes more vertical.  In mathmatical lock step with the increasingly vertical arc, we must know target distance to more and more precise value, or risk missing the target because of errors of just a few yards.

LRF laser beams in the first generation equipment were barely capable of ranging a cow at 500 yards.  Their lasers were not very well colminated (parallel) and didn't have much power.  In addition they didn't always use the best frequency (color, wavelength, etc.) to reflect off of the types of targets shooters (both hunters and target shooters) were trying to range.  Cabelas, Nikon, and other consumer LRF's in the sub $500 range are representative.

In the second generation of consumer LRF's the beam colmination and power went up considerably.  Ranging a standing cow at 1,000 yards was now run-of-the-mill.  Gunwerks G2BR (original) and others costing over $1,500 are represnentative.

By 2018 several manufacturers were competing for the extreme long range shooters dollars and thus constructed what I'll call the 3rd generation of LRF's. These generally are capable of ranging a standing cow at somewhere beyond a mile.

To achieve these improvements the laser beam had to be more parallel, contain more power and reflect better.  The detector had to become more sensitive too.

Wikipedia: Laser Rangefinder
Wikipedia: Beam Parameter Product





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Precision Rifle Cleaning Protocol

Your new precision rifle comes from the factory after being fabricated and tested. Depending on the factory, and the order specifications for your rifle, it may have had the bore cleaned and a thick protective coating of Cosmoline, oil, or machine coolant . In any case, it is in the best interest of barrel life, that your first act upon receiving a new rifle (from any source) is to clean and inspect the barrel.

Initial cleaning to remove factory coatings may be accomplished by plugging the barrel at the muzzle end, placing the rifle muzzle down (on a drip pan), and spraying a lot of WD-40 into the chamber end. Leave the WD-40 to dissolve anything left over from machining in the barrel for 10 minutes, then drain and wipe out with a cleaning rod and patches.

Cleaning Rods, Accessories and Chemicals

One of the challenges of cleaning a rifle is to not get cleaning solvent into places it doesn't belong.  One of the best methods I've found to do that is to purchase the appropriate 'Possum Hollow' bore guide and solvent port adapter.  Once installed this bore guide keeps everything out of the chamber, and everywhere else that isn't the bore.  You'll want to clean the chamber separately.

NOTE: Cleaning using long shoe string style tools is perhaps useful in some environments, and for some pursuits.  In my opinion, it is not appropriate for precision rifle cleaning, and should never be used in precision barrels except as a last resort.

NOTE: Cleaning rods come in a wide range of styles.  For precision barrels, steel rods are out because steel is hard enough to destroy the interior of the barrel.  Brass is softer, yet it to can damage the barrel if misused repeatedly.  This leaves us with coated rods and carbon rods.  I prefer Gunslick Carbon rods and their brass rifle jags.  I do not find any reason not to use J. Dewy rods, however read their disclaimers about corrosion and fitting.  Both style rod come equipped with a ball bearing handle, which I prefer.  J. Dewy has a line of jags and tips that do not react to the chemicals typically used to remove copper, so they don't produce a false positive reading, which you sometimes get from a brass jag.

NOTE: Cleaning patches from Montana Extreme seem to me to be the top of the line for use in precision rifle barrels, and there's nothing wrong with their cleaning rods as they are coated.

NOTE: Cleaning Solvents from KG Coatings are useful because they are specific for Copper or Carbon.  Few of the mainstream manufacturers listed above have differentiated solvents.  It is important to be able to remove only Carbon and leave Copper intact in the barrel.  KG-1 Carbon remove does just that.  It is difficult to remove Copper without damaging the barrel.  KG-12 removes Copper without any chance of damage to the bore.

NOTE:  Gun oil (KG-410) is a fine oil for protecting and lubricating as necessary however, I have found MILTECH-1 Weapons Lubricant lives up to its advertising, and is extremely useful as a bore conditioner.

Cleaning For Accuracy

Some folks believe the best accuracy can be obtained by cleaning everything out of a barrel as often as possible.  This philosophy has won bench rest competitions, but is not practical for weapons used in the real world where many shots are fired between cleanings.  Our challenge is to analyze what occurs inside the barrel with the first shot, and subsequent shots, and why accuracy falls off over time if the bore is not cleaned, and what to remove, and when.

As the bullet moves into the barrel, pressure rises to its maximum typically within the first 6 inches of travel.  At this point the temperature has also reached maximum and there is still a lot of unburned powder being accelerated down the barrel.  The bullet jacket has been forced into the rifling and the bullet is beginning to accelerate very quickly.  The hell that exists inside the chamber and first few inches of the barrel is so intense that it will erode the machining, and leave the surface of the barrel checked and crazed.  There is little that cleaning can do to alter this condition, nor prolong its useful lifetime.

As the bullet moves further along the barrel pressure and temperature of the gas drops quickly and significantly to the point it no longer poses a threat to the barrel material or machining.  Bullet velocity has increased substantially, and now jacket material is melted and pressed into whatever irregularities exist, particularly onto the lands (raised surface of the rifling), and the corners of the bottom of the grooves, and machining marks along the bottom of the grooves.

As the bullet continues to accelerate in the last 1/3 of the barrel, it reaches its maximum velocity, and the frictional heating of the jacket is at maximum.  This is the area most likely to see heavy copper plating.

When the bullet exits the barrel, the gas and residual debris are ejected at a speed much greater than the bullet, but some of the debris nearly always remains in the barrel.  This material is mostly carbon.

When the next shot is fired, whatever carbon is left in the barrel is pounded into the barrel by the bullet, or is ejected ahead of the bullet.  Given the very acute angle between the bullet ogive and the barrel, a lot of the carbon is trapped and pounded into the barrel walls.  Some of the copper that is deposited by this shot will have a carbon layer under it, and some will find either bare steel, or previously deposited copper to adhere to.

When subsequent shots are fired, whatever material that can move is ejected ahead and behind the bullet, and the remaining material is again pounded into the walls of the barrel.  Copper continues to adhere, mostly to locations where it has begun to plate the surface.

As the first shot is fired, a certain resistance to the bullets movement down the barrel occurs.

As the second and sometimes a few more shots are fired, each experiences a slight increase or decrease in resistance to movement as a function of the lubricity of the material previously deposited in the barrel, and the changes in that materials distribution.

At some point an equilibrium is established where each subsequent shot feels essentially the same degree of resistance to movement, and at that point muzzle velocity variation is reduced, and accuracy begins to occur.

This condition will persist typically until carbon buildup causes a loss of accuracy, which in my 6.5 Creedmoor H4350 load has been found to be at about 300 round intervals.  In my 308 Winchester Varget load, the interval is closer to 400 rounds or more.  In my 204 Ruger Varget load, the interval is about 100 rounds.  In my SR556 CFE223 load the interval seems to be greater than 500 rounds.  From this I conclude that the available surface area of the barrel and the carbon debris load of the powder are the controlling factors determining when accuracy is degraded and how often a carbon cleaning is required.

CARBON Cleaning Cycle

To restore accuracy when carbon fouling has degraded it, all that is required is to run a carbon specific cleaning cycle.  I use a nylon brush of the appropriate size, soaked with a few drops of KG1 and quickly run the brush all the way down the barrel and out the muzzle, then back into the bore guide body for a count of 1.  I repeat to a count of 25 as quickly as is practical (KG1 is designed to work best when agitated this way).  Then I run a patch soaked with KG1 through and out the muzzle.  This patch will be extremely dirty.  I repeat the KG1 patch one more time, this patch is almost clean, so I repeat again and the 3rd patch usually comes out with no carbon at all.  At this point I wet a patch with MILTECH1 and scrub the barrel in 4" sections from end to end to ensure the MILTECH1 is reaching into all available spaces.  Next I make a point to fire the barrel 3 shots before I put it away to get the MILTECH1 up to operating temperature, and to season the barrel for the next cold bore shot.  This is probably me being OCD, because typically those three shots all go into the same hole.

I am totally convinced that the MILTECH1 routine inside the barrel has stabilized the accretion of copper and distribution of carbon in such a way that it has made the barrel generate more uniform velocity.  I'm also convinced the MILTECH1 is responsible for the extremely fast carbon cleaning cycle.

Carbon cleaning cycles are so quick and easy I carry the required material in the gun case, and can do one of these anywhere, anytime in just a few minutes.

COPPER Cleaning Cycle

At some point in the future, a carbon cleaning cycle will not restore accuracy to the customary 0.25 MOA, and I will decide it is time to do a copper cleaning cycle, which goes like this;

First do a carbon cycle but omit the MILTECH1 finish.

Perform the same nylon brush treatment using KG12 and 25 strokes followed by KG12 soaked patches.  Watch the patches for blue streaks which are dissolved copper.  Repeat the KG12 brush routine followed by the KG12 patches until no streaks are present.  Follow the KG12 routine with a degreasing using brake cleaner soaked patches and/or rinsing the bore with brake cleaner.  After degreasing, MILTECH1 the bore, and wipe KG4 Gun Oil liberally on all other surfaces.  KG4 can be left on for storage.  Put a note on the rifle to MILTECH1 again, and perform a break-in cycle before next use.

Copper cleaning cycles generally involve more material than I carry with the rifle, and typically are not as critical to be able to perform in the field, so they are accomplished back in the shop at home.

Barrel Break-in Cycle

  • Clean the bore.  Clean it to bare metal using the Copper cycle with degreasing and finish with MILTECH1.

    The idea is to allow copper to steel contact so as to increase copper deposition quickly.

  • NOTE: The idea is to achieve muzzle velocity variation stability.  If you know the typical ES (extreme muzzle velocity spread) for 5 shots from this barrel when seasoned, and you see that the ES is at that level after just a few shots into the 5 at a time part of the protocol, I recommend you consider the break-in complete and move on.  If on the other hand, ES is still high, continue with the 5 shot portion of the protocol until ES drops to previously recorded low number or below.  This comment is also valid for initial break-in, however since you have no data on previous ES with this barrel, you can only be guided by raw numbers.

    Using my 6.5 Creedmoor 143 ELDx 2652 fps load, changing the MV and looking at the come up predicted by Applied Ballistics Mobile we find the following:
    So in this load, a variation of +/- 25 fps results in an impact variation of 1.25 MOA
    If we distribute 10 shots evenly over the 50 fps variation the SD would be: 16.02
    Were we to have 5 shots at each velocity, even though the ES remains 50, the SD becomes: 26.35
    If we change the number of shots to 5, and set the ES at 25, with an even distribution of velocities the SD becomes 10.1

    In summary, when performing a break-in cycle, once you are into the 5 shot and repeat loop, if you see your ES for 5 shots at or near 25 fps you can probably stop the break-in cycle with no adverse effect.


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    ADDITIONAL STUFF YOU NEED

    Here is where I will post articles describing things I've purchased, modified, or engineered from scratch to use in pursuit of accurate long range shooting, precision reloading, or any related topic.

    Portable Shooting Bench

    Eric and I have been building and testing shooting benches for a while now, and I think my latest design is pretty close to the ‘perfect’ portable shooting bench.

    So what does ‘perfect’ mean in this context?

    1. Light enough to move any component easily with one hand at full extension.
    2. Minimum number of components.
    3. Sturdy and stable enough to realize about 95% of the accuracy of your rifle.
    4. Comfortable enough to spend all day shooting.
    5. Large enough to support load development (clipboards, chronograph, portable computer, ammo, small stuff.)

    To build this bench you’ll need to be able to cut pipe fittings at accurate angles and cut 1/4” flat steel bar at 90°.  Both of these operations can be performed using a cheap chop saw which you should buy used at a pawn shop because when you get done cutting metal (with a cut-off wheel) the saw won’t be any good for anything else.

    In a quick Google search I found a used Delta 10” Miter Saw (SM100M) for $39.99.  In the same search I found cut-off wheels for metal cutting in the range of $5-$10.

    SHOPPING LIST - Total Bench & Legs: $155.56.  Total with Gibralter stool: $230.51
  • 1-1/8 x 23-1/4 x 48 Edge Glued Board Homedepot $25.55
  • Cold rolled steel flat bar 1/4”x4”x24” ($16.17 on eBay ships for $16.33) You may find this locally for less.
  • 1” NPT coupling 3 each, select the longest available, (makes 6 attachments) Homedepot $2.95/ea.
  • Legs 1” x 36” pipe 3 ea.  Homedepot $13.65/ea. 
  • Feet 1” NPT pipe caps 3 ea.  Homedepot $2.49/ea.
  • Helmsman Spar Urethane 1 qt. Homedepot $16.57 or 11.5 oz spray $9.56\
  • Two coats of Spar Varnish initially, repair coats annually.  Obtain a can of cleaning duster like for your computer - use it to displace air [oxygen] before re-sealing the urethane, it will not skim, and will be ‘factory fresh’ to the bottom of the can if you do this every time.  Make sure you have mineral spirits available for thinning and cleanup.  I use heavy duty Nitrile gloves for reloading (keeps hands clean, better grip and no oil transfer), if you’ve got ‘em use ‘em while varnishing too.

    CONSTRUCTION

    Screw the coupling onto one of the legs, just enough to hold it firmly.  Set the chop saw with the cutoff wheel installed to cut 14°.  Cut the coupling into two even halves.  Use the leg to control the work, watch out for sharp edges and hot material!  Do this until you have 3 ea. couplings with sufficient thread to hold the legs firmly.  (I think maybe an angle of 7° would work a little better but I haven’t tried it yet.)

    Reset the chop saw to 90°.  Accurately measure the flat steel bar width, and cross cut it to be square.

    Using a drill press if you have one, or a hand drill if you must, drill a 9/32” a hole centered 3/4” in from each edge, at each corner.  Chamfer all cut edges on all pieces.

    Set the couplings onto the 4x4 attachment plate.  Place two of the cut couplings at 45° and one at 90° (45° points to a corner, 90° to the middle).  Weld the couplings in place.

    Prepare the bench top by cutting out the area to sit in, I made mine for a right handed shooter by cutting out an area roughly 12” long x 9-1/2 wide on the left back corner.  I found that clipping the outside corner a little and sculpting the line eased a ‘poking’ problem when I was up tight on the rifle.  Make sure you leave room for the leg attachment to be on the centerline, and all the way back to the edge.  Cut all sharp corners at 45° (say about 1” back from the corner).

     Sand both sides of the bench to 220 grit.

    Using a 45° chamfering bit in your router ease all of the edges on both sides.

    Turn the table top upside down, place the forward leg mounts so the couplings point forward and outward.  Move the plates until they are 2” in from each adjacent edge, then drill a very small (1/16”) hole in the exact center of each hole in the plate.  

    Flip the top over to right side up.  Use a 3/4’ Fortsner Bit to create a 1/2” deep pocket for the bolt head.  Center the Fortsner on the 1/16” hole.

    Flip the top over to the underside.  Replace the leg attachments.  Drill a 9/32” hole all the way through at each attachment point.  

    Touch up by sanding to 220 again.  Tack off with a cloth dampened in mineral spirits.  Following the direction on the can of spar varnish apply one coat on each side.

    Sand to 220 grit to level the spar varnish, and apply a second coat.  If you are working in the shade at 60℉ this coat should be able to be brushed on as a flood coat if you work quickly.  Watch for runs and clean them up as best you can.  If you thin the Urethane slightly with mineral spirits you can get the 2nd and subsequent coats to come out like glass.  Be sure to get varnish into all of the holes (natural and man made).

    Install the leg holders with 4 ea.: 1/4 x 20 - 1-1/2” carriage bolt, 1/4” washer, and 1/4-20 self locking nut (nylock).  Because the laminated pine top is rather soft, the carriage bolt may try to spin as you tighten down the nylock.  You can reduce the tension of a nylock by running a tap from the bottom of the nut until some of the nylon has been cut away.  Test until you find how much you need to cut, then do all the nuts.  Alternatively use regular nuts and a thread locking compound.  Be careful not to over tighten the nuts.

    Find the center of gravity (test balance side-to-side, then front to back, mark the intersection), and install a handle on the bottom  centered on this point.  I put mine at 45°, and so far it seems to be working.  You might want to put one pointing each way, or you might want to use a round knob type handle.

    You may want to run a wire brush up and down the legs then paint them with a metal paint, and install the caps with more force than you can apply by hand (and/or use a thread locker here too).  Those caps may be all that gives you the necessary torque to remove a leg in the field.  (if your legs tend to stick, you can drill a hole sized for a screwdriver or something … that will also help you tighten them down, but I haven’t found it necessary on my bench yet.)

    For extra credit you can setup two of the legs with slip-fittings and coordinated through holes to accept a clevis pin. This will allow you to adjust the bench for up/down and left/right to accommodate shooting in a hilly environment.  Imbed a circular level in the top to aid in setup.  Alternatively just take a small shovel along to change the level of dirt under the leg(s).  (I’ve always got a small pick and a small shovel on the UTV for sanitary and brush fire use.)

    Last but far from least is something to sit on while you shoot.  I tried several stools, buckets, milk cartons and such.  Each had problems that could only be overcome by becoming a furniture maker.  Then I tried Gibraltar 9608 drummers throne.  This is worth every penny in my book.  The seat is very comfortable for long sessions, is easily adjusted for height across a range of 21”-30”, and perhaps most important, the feet are really large, and where we hunt the ground is very soft, with lots of squirrel holes and tunnels.  These feet really work.  I did manage to find what I think is the best price from Musicians Friend at $74.95 with free shipping. 

    You can help yourself justify the Gibraltar when you realize you can also use is as a seat at the reloading bench, and/or the computer desk, or whatever.  This seat is very versatile and extremely comfortable. 

    Gibraltar Drummers Throne
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    Light weight, compact, sturdy shooing bench

    This bench sits on edge, and takes up very little room in the back of the car!
    Shooting Bench 1

    Rear leg is on the bench center line, leg points straight back.
    Shooting Bench 2

    Right front leg attachment.  Points out at 45°.
    Shooting Bench 4

    With legs attached you can easily see the angles: 14° and 45°. Leg are 36” long.
    Shooting Bench 5

    Bench setup with Gibraltar drummer’s throne.
    Shooting Bench 6

    I am working on a leg transporter that will secure the legs, and I plan to paint the legs flat black. I’ll make that the subject of another missive.
    In case you are wondering, the pockets for the bolt heads have not interfered with either bipod or mechanical rest use.

    Here is the drilling template for a simple carrier for the legs.  All you need to do is print it out at 1:1 scale, twice, stick it onto two pieces of 3/4" solid wood, and drill the holes as shown, then cut away the scrap, leaving 3 half holes about the center on each piece.  Connect the two pieces with a convenient length of something not over 0.870" diameter, so use a 3/4" rod.  Place the legs into the cutouts and then tie them up.  I use a Niteyes Gear Tie, but anything from shoelaces to pipe clamps will work.  Once tied to the carrier, the legs and carrier act as a single unit making it much easier to carry.  Add a strap to the carrier and you can go hands free!


    Leg carrier in use

    Leg carrier detail

    NOTES:

    Since I built the shooting bench to transport on my UTV, I've sold the UTV and bought a Hummer H3 ... and installed a long roof rack.
    The bench with it's legs easily fits inside the roof rack, along with two or three of the Portable Target Stands (below).  Pictures when I think about it.

    While the bench was onboard the UTV over the winter rain caused the leg's threaded segments to rust.  I wire brushed the threads put lithium grease on all of the threads.  That corrected the rusting problem and made the legs easier to install and remove, but the grease wanted to get all over everything.  I put threaded PVC pipe caps on the legs to act as thread protectors and to protect everything else from the grease.  So far it's working, just have to keep track of the caps when the bench is deployed.


    UNDER DEVELOPMENT

    Bibliograhpical Links

    US Army Aberdeen Proving Ground RDECOM Research Laboratory Technical Report Search Page


    Additional Tools and Software