Trigger Pull Weight

I have been having ‘issues’ getting an AR platform to shoot accurately. One area often mentioned as being first or second in importance to delivering accuracy is the trigger. I have been shooting a Ruger Enhanced trigger in the SR556 lower since the beginning of the project. Its a good trigger, and I thought I could shoot any trigger well enough to get under 1 MOA (I still think that’s true).

I’ve upgraded the lower; Trigger Tech Adaptable Primary Trigger single stage trigger w/straight trigger face, set to about 2 lbs, LUTH-AR MBA-3 buttstock, and a ‘nice’ grip (not a vertical – that’s next).

The barrel(s) and upper receivers are assembled correctly and barrel nuts are torqued accurately (to 50 lbft at the moment) with Copper infused anti-seize grease on all of the threads and the barrel extension/tenon. I’ve learned how to install the gas tube so there is no strain and I’ve installed adjustable gas blocks on each of the test barrels. The scope mount has been upgraded to a very stiff Warne XSKEL QD mount that actually holds zero between moves, and has a predictable POI offset between uppers.

You can read about the build, and various issues in other posts on this blog. (NOTE: Some of those are still under construction as of 20200819)

In short I’ve done ‘everything’ and I still can’t get under 1 MOA consistently.

So I got to wondering about the trigger. I like my rifle triggers at 2 lbs, and on a bolt gun that has measurable value in executing the shot when the sights are aligned. In the AR adjusting the trigger that low has caused me to ‘double’ a couple of times when I didn’t want to while shooting ground squirrels.

I decided I needed another tool so I had Amazon send me a Wheeler digital trigger pull weight gauge. Nice tool! A little bit difficult to get consistent readings unless you are very careful not to continue increasing the pull weight after the trigger breaks. This is difficult with the Trigger Tech trigger because it has so very little overtravel. Another thing is that the Wheeler tool only provides pounds and ounces, no decimal pounds. You’ll note I used a ‘.’ in the column names used for converting into decimal units.

Now that I think I know how to use the trigger pull weight gauge, I started testing the guns I have at hand … and here are some of the results.

Trigger Pull Weight Analysis

I don’t think in pounds and ounces, so I converted the test data to decimal pounds and calculated an extreme spread in both ounces and decimal pounds to give sense of the variability of that trigger.

The Remington 700 has a very expensive custom trigger job on the stock factory trigger.
All other triggers are stock ‘as issued’ unless noted.
The Trigger Tech still has my vote for the best rifle trigger in the bunch because it is as good as the Remington custom job, and also is adjustable. I’ve decided to try it at 3 lbs to see if I can get under 1 MOA with it, and come squirrel season we’ll see if that’s enough to keep from doubling.

As for the pistols and revolver, the Kimber CDP II was my ‘gold standard’ trigger. Perhaps it’s not fair to compare it to a trigger 40 years it’s senior, but the Uberti has show its self to be very predictable and light. In fact shooting the Uberti is a pure joy, and now I can show you why. Sometimes simple is better. The Taurus – my EDC, has a striker. It can be fired after being cocked (in the usual manner), but also can be fired simply by pulling the trigger again. I call that a ‘RESTRIKE’ capability. It has a long heavy trigger pull that is about 1/4 lb lighter in restrike mode, but quite smooth and predictable. The feel between the two modes is only that restrike is a bit lighter, travel, break, etc. is identical. The Ruger Security Six revolver has had some trigger work done to smooth it out and reduce mainspring to still fire reliably, while reducing trigger pull weight in double action. I was missing my old S&W 686 Shilouette match winning 44 MAG, and picked this revolver up for next to nothing and did the action work myself. On good days I can still hit clay pigeons at 100 yds double action with this gun.

In any case, the argument I was having with myself over the ‘quality’ of the Trigger Tech trigger vs the Savage 10 and the Remington 700 is settled, so now I can quiet my brain and concentrate on learning to make the AR platform shoot like a 12 pound varmint gun …

And, while on the subject of analyzing everything, another thread of thought was that the Dillon XL 650 powder measure might be having too much variability and that the RCBS Charge Master might be drifting too much, so I found an $18 ‘Brifit’ scale on Amazon that claims roughly double the resolution and accuracy of the Charge Master. It appears to be quite stable. It needs to have a bit of weight to start sensing, but once the display starts it will update the display for a change of about six kernels of Varget, and based on what other’s have said that’s about right for a resolution of 0.01 grains. Future loads used for accuracy or long range will be checked for accuracy and consistency to this level and loaded by hand (rather than on the Dillon) using Wilson hand dies. Once I find a load and seating depth that works, I’ll see how much leeway there is in powder charge and seating depth.

Here’s hoping the heat goes away soon!