Trouble with PEPR and/or sudden loss of accuracy

[Nate]

I have seen a barrel nut work loose and drive a friend close to the edge. It is a bit of a PITA but might solve the problem.

[jkmccoy]

If anyone is still curious, I've fixed the problem. The rifle is back to shooting reliable 1.5-2.0" groups at 100 yds. I'm sure there will still be lots of speculation about what was the problem.

Yesterday I disassembled the upper. I removed the Samson rail. I removed the home-made comp. I removed the scope and mount. I removed the gas block and gas tube. I unscrewed the barrel nut and removed the barrel.

I cleaned all of the parts thoroughly. I re-installed the barrel with a different barrel nut torqued to 65 ft-lbs. Reinstalled the gas block and tube. Installed a Miculek comp. Reinstalled the Samson rail. Reinstalled the scope and mount.

At the range today the rifle shot much higher than it had been. I adjusted the scope and moved to 100yds. I shot a bunch of 5-shot groups. All about 1.5-2.0 inches (see below, these are groups shot at 100yds). All groups were reasonably round and without obvious vertical stringing. The last time I was at the range the rifle was shooting groups 8-10 inches tall at 100 yds.

Although it's possible that the problem was the compensator, I think the problem was the barrel nut. When I removed the first barrel nut it was obvious that it had only been in contact with the shoulder on the barrel exension for about 1/2 of the circumference. It was also much easier to install the rail on the new barrel nut and it was no trouble to tighten the rail parallel with the barrel.

Thanks for your suggestions and helpful comments.

Kelly

Edited October 21, 2013 by jkmccoy

[jh3g]

If anyone is still curious, I've fixed the problem.

Thank you for taking the time to follow-up on this post. Glad to see that you got everything sorted.

[hunterdmw12]

so now try to put your homemade comp on and see what it does

[chevyoneton]

Thanks for the follow up and glad you got it sorted. Just for historical purposes I have a QD PEPR holding a MTAC and have never had any issues, even after removal and re-install. I do keep it pretty tight though. I really like the adjustment on the PEPR QD screws/nuts in this regard. Once upon a long time ago, I had a Savage 110 7mm Mag with Leopold 3X9 bought cheap at a pawn shop. It would not shoot any kind of group. I tried several different kinds of ammo over many, many range sessions but nothing worked. I made up my mind to sell the turkey but took it to the range one more time. It shot little bitty consistant groups, but it was too late as I had already decided to sell it off. I removed the Leopold and sold the rifle for what I originally paid for the whole rig. Put the scope on a Remington 700 25-06 and it is the most accurate rifle/scope combo I have ever owned/shot. The world is good. Sorry to drift off topic.