12-18-2018, 04:55 PM
rebby Wrote:I bought both a stainless and a nitrite version of these. Ive only shot the nitrite gun so far and was getting groups in the 1-2 range @ 50y (off the bench with an S&B Polar in a Geissle mount). I tore it down a few days later and found that the barrel nut was torqued obnoxiously high, there was a quite a bit of slop between the upper and the barrel extension, and the flash suppressor was tightened until the crush washer was flat. Prior to reassembly I cleaned up the chamber and feed ramps a little although they werent terrible out of the box. I also lapped the upper and reassembled with Loctite 620 torquing the barrel nut to a much more reasonable value (I did the same with the flash suppressor). I still have a little work to do with the bolt/BCG but I wont get crazy with either. Due to what I found on the nitrite gun, I preemptively went after the stainless upper and found it to be built in the exact same manner.
Im hoping that this little bit of attention tighten the guns up some but dont have crazy expectations either. Im essentially looking for a lower cost alternative that can be made to shoot well with minimal effort. If a barrel R&R and some quick polishing can do that for me, Ill have a winner. Now Im just waiting on some decent temperatures to get back out to the range.
What type of accurizing are others doing with these? Any really promising results yet?
I finally have an update to this. Sorry for the delay, it's been a busy couple of weeks (my 8 year-old had another, expedited, surgery). Anyway...
As I mentioned in the quoted post above, I did a little work on both guns. I ended up replacing the crush washer on the nitrite gun with a Accu-Washer from Precision Armament (these are phenomenal BTW) and ran the stock A2-style flash hider. I left the FH off of the stainless gun and just spun on a thread protector and snugged it up by hand. I did a quick clean of both barrels using Hoppes #9 followed up with some clean/dry patches.
Starting with the nitrite gun, initially I was seeing 1-2" groups at 50y out of the box. Results this time around were significantly better, I didn't have a caliper with me but this time I managed roughly 1/2" at 100y. Two of the rounds went through the same hole (for the most part) and the third hole was just outside of "cloverleafing". I only shot a couple of groups yesterday but this 3-shot string was pretty representative of my results, the largest group was still <1". Groups were all shot using 120g Nosler ballistic tips from Alexander Arms with a Schmidt & Bender PMII @ ~12x in a Geissele SP mount using a Magpul bipod and a rear sandbag off a bench. This gun will likely end up with an MRD/BUIS set up in the end (which is why I didn't adjust for a better POI).
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I shot a few more rounds through the stainless gun than the nitrate one. As I mentioned previously, I preemptively "reworked" the stainless gun so yesterday was the first time that I ever shot it. Groups were still quite good however. The pic attached is a 5-shot group at 100y with, of course, the final round sneaking out to the right totally destroying the final group. Still, this is representative of what the groups looked like all day. I started off with a little vertical stringing that (obviously) settled down as the day went on. The string never got any worse than ~1.25" @ 100y though so it wasn't anything that really concerned me. Groups were all shot using 120g Nosler ballistic tips from Alexander Arms with a Vortex Razor HD LH @ ~8x in a Aero Precision SPR mount using a Magpul bipod and a rear sandbag off a bench. I intend to keep this scope/mount combo with this gun in the long run.
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Both guns were shot with the same Six Sigma Arms lower equipped with an AR Gold trigger adjusted to 3.25lbs.
At this point I'm thrilled with what I've been able to squeeze out of these uppers after a quick rebuild. I'll continue testing with some additional loads and I'm going to see if I can tame the recoil a bit with an APA Little Bastard brake. I'd really like to get these both setup for deer/hogs for my kids (my youngest is currently 8).