TA31F inspired spare parts build

[Rmorris]

I like the TA31F for what it is, light weight, durable, simple, and combat proven. It is not, however, my preferred optic for a serious civilian rifle. I bought this scope years ago and it has been back and forth on several builds, but it has been sitting on a shelf for several years. I decided to build a rifle around it.

As such, the goals was a durable light rifle, like the ACOG, with an eye toward using its reticle to its fullest.
I decided I should free float a decent barrel, and use a decent enough trigger. I would use as much as I could from the spare parts I had laying around, so long as it was quality, but buy whatever was needed. This will not be the rifle I keep for serious or defensive use, and I have other ARs with other (better) ammo for that. However, life can be unpredictable, so it will be built with a core of go to war, quality parts.

The TA 31F is a red chevron with BDC ladder. It is a sort of compromise, civilian oriented reticle. It is geared to a 55 grain bullet from a 16 in barrel and its BDC is in meters. The width of the lines corresponds to human width at the corresponding range. It is about the same size as a small pig or the distance between the front and back legs on a coyote. 100 yards is roughly 110 meters, so the math is pretty easy, working down the ladder. A perfect match in yards to the reticle in meters would therefore be 110,220,330,440,550,660,770. You see it is pretty close.

I will rough zero at 110 yds then fine tune a 330 yds zero using the tip of the post to minimize error and spin drift effect at range.

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This rifle is made to take advantage of cheap surplus 55 gr ammo, but I will put back a stash of some varmint and other 55 grain stuff to use as needed. It may see some hunting use in the spring and summer for coyotes and pigs, but will likely stay at home during fall hunting season, in favor of something bigger. As such, it got a more green phase rattle can job that will work in west Texas during those times. I’m torn on the MFT stock and the Proctor sling, but they were in the drawer, so on they went, and they are both quite light. An Ergo grip of a personal favorite. All my rifles are set up with enough 6 o’clock rail to attach a bipod. This also helps hold the sling on.

I looked into lighter weight barrels and decided this might see a pretty decent volume of shooting, so I opted for a Daniel Defense CHF chrome lined mid length light weight barrel. It has a reputation for accuracy among light barrels, and it is a little more substantial than the thinnest barrels. I also wanted the pinned gas block, and when I found it on sale, I jumped on it. It was one of the few parts I opted to buy.

The buffer tube, spring, buffer, bcg and handguard are all BCM. I think the upper is BCM, it is about all I buy for forged parts. The trigger is either BCM PNT or an ALG coated and improved mil spec single stage. It is an H2 buffer for now.

Everything is staked and marked with a witness mark. I can’t think of anything else to do, but maybe add a CTR or BCM stock if I hate this one. Any other ideas?

Rifle photo and range report to follow…

[Rmorris]

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As promised.

[gaijin]

Looks good. I’d throw on a WML.
I tried an MFT and went back to BCM and B5 SOPMOD.
I found the Procter sling to narrow and use several Ferro Concepts.
Of course, use it as built and decide what is working for you and what, if anything, is not.

[Rmorris]

Well the DD barrel shot well with 77 gr ammo, but not any variety of 55’s.

I will set the DD aside for a serious use rifle. I have 3 sons and have built rifles with 2 of them so far. It will be a good intro to ARs for the youngest some day. There is always a place for a 16 in lightweight.

I have an old preban 16 in 1/9 somewhere, from the ABCD days, collecting dust. I never thought I would use it, but this seems like the place. I’m sure it is not a lightweight, so the MFT will get swapped to something heavier to help balance it out. I may even have to cut some M4 feed ramps. I’m determined to have something that works with this scope.

I am not sure how well this trigger is going to work, but I will stick with it for now. A thousand round trigger job will likely make it nice, but I’m inpatient.

Gas, buffer, etc was fine. Function was flawless, but I’ll be messing with it again so that is irrelevant for now.

I think I will swap an old SF scout light from another build and try something new to replace it.

[Disciple]

Well the DD barrel shot well with 77 gr ammo, but not any variety of 55’s.

What performance were you getting from each? (77 and 55.)

[Rmorris]

10 rounds of Norma 55 into 2.4 was the best of the 55. Most of the rest of the 5.56 m193 Fed and IMI groups were 3-4. Tula, run just to confirm function, was like 5 MOA. Not too surprising.

I had a box of AAC 77gm MHP 5.56 in my range bag and it went 10 rounds into 1.1 and 10 into 1.7 MOA.

Not an extensive test, about 100
down range, with some time for cooling. I bet the barrel tightens up some as it breaks in.