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View Full Version : AR Build Range Report - Plus a few issues



jjl103
3 February 2014, 11:58
I posted my AR build in the stickied thread, but just got around to shooting it a good bit this past weekend. I splurged on a 500 rnd case at our local gun store, so I ended up putting 150 of the cheap AR225 black boxes through it. I was pretty impressed with how controllable it was (just over 8lbs loaded with a 30rnd PMAG). There was definitely a noticeable difference between the Surefire MB556k and the regular A2. My MBUS Pro sights were pretty easy to get zeroed in, and the Vortex Sparc stayed zeroed despite somewhat banging it around.

I did encounter a couple of issues. I mentioned on my last post that I took some shortcuts on the buffer kit (cheap ATI), and I definitely noticed the difference. My STR stock had for some reason been pushed all the way forward (i had it taken apart prior to shooting it), and I didn't think to check the length on my first shot. 3 shots later, I noticed it was too far forward, but when I went to adjust it, I noticed the STR had gotten stuck on the rigid threads of the ATI Buffer Tube. I spent an hour of my time pulling on it and prying it off, finally getting it free. Its flaw is that the threads weren't tapered, they just end. Quality tubes would have a taper or sanding down, to fade them so stocks don't get stuck. I even noticed this craftsmanship on the PSA tube my friend was running. Needless to say, I purchased a new kit that shipped out today.

I found that I had only 1 failure to eject out of the 150 rounds of brass I shot (last round in my 2nd magazine didn't eject or hold the bolt open, however I couldn't repeat the results in the remaining 3 mags). I also tried a box of Tula Ammo, which did not function at all in my gun. I experienced failure to feeds, failure to ejects, and double feeds. The failure to eject happened every other round. I got a failure to feed probably every 5 rounds, and I experienced 2 double feeds as well. This was out of just 1 box of 20. Definitely think this has something to do with the 14.5" Midlength not liking the under pressured rounds, as I tried my friend's upper (16" middy) on my lower and it worked without a flaw.

Other than that, it functioned fine and I was able to shoot 1 MOA groups from 25m out with the Vortex Sparc, which I think is a definite win.

rxer311
3 February 2014, 16:43
Failures with Tula are common. Is your rifle a midlength?

None of my middies will eat Tula and it produces the same results you described.

I just built my first carbine length rifle specifically to shoot the cheap Russian crap and it does so without any problems.

FortTom
3 February 2014, 17:45
Failures with Tula are common. Is your rifle a midlength?

None of my middies will eat Tula and it produces the same results you described.

I just built my first carbine length rifle specifically to shoot the cheap Russian crap and it does so without any problems.

Hey guy's, not trying to hijack the thread, but Wolf makes some ammo now that uses re-loadable brass, standard copper/lead FMJ w/ sealed boxer primers, and sealed at the cannalure of the bullet. $6.99 a box. I tried a couple of boxes, to see (because it was from Wolf, maker of Russian crap) if it was too good to be real. Ended up ordering another case. Got it at AIM, if you're interested in some cheap but very decent quality practice ammo. O.K., back to the thread. I've had trouble with Tula too. I won't buy the crap anymore.

Good luck with the new build.

FT[:D]

AR-10
3 February 2014, 18:39
That ATI receiver extension is actually a "commercial" tube.

Commercial receiver extensions have cut threads, and the threads will be the same diameter as the tube.

Mil-spec receiver extensions have rolled threads, and the threads are actually slightly larger than the rest of the tube.

This is the "taper" you are referring to, and is one of the reasons why you should choose mil-spec over commercial.

Your STR stock might be the mil-spec version, which is why it is tight on that ATI tube.

jjl103
4 February 2014, 19:01
Hey guy's, not trying to hijack the thread, but Wolf makes some ammo now that uses re-loadable brass, standard copper/lead FMJ w/ sealed boxer primers, and sealed at the cannalure of the bullet. $6.99 a box. I tried a couple of boxes, to see (because it was from Wolf, maker of Russian crap) if it was too good to be real. Ended up ordering another case. Got it at AIM, if you're interested in some cheap but very decent quality practice ammo. O.K., back to the thread. I've had trouble with Tula too. I won't buy the crap anymore.

Good luck with the new build.

FT[:D]

Yeah, I've seen that. I found some pretty decent deals here on bulk 5.56 ammo, so its not like I have to resort to the TA right now.


That ATI receiver extension is actually a "commercial" tube.

Commercial receiver extensions have cut threads, and the threads will be the same diameter as the tube.

Mil-spec receiver extensions have rolled threads, and the threads are actually slightly larger than the rest of the tube.

This is the "taper" you are referring to, and is one of the reasons why you should choose mil-spec over commercial.

Your STR stock might be the mil-spec version, which is why it is tight on that ATI tube.

This particular buffer kit said "mil-spec". The STR wasn't really all that tight on the buffer tube, it just got jammed on the threads. The diameter is mil, just the quality sucks.