I have a Professional Ordinance Carbon 15 rifle. I have had it for 6 or 7 years, but never been able to get it to shoot very accurate.
It will put 2,3 or 4 shots into a fairly tight group, then the next group will be in a 3 or 4 inch pattern. And this is at only 50 yards. Can't seem to find any rhyme or reason for the patterns either.
I have exchanged scopes, mounts, let the barrel cool, shot w/o the muzzle brake/suppressor, extra barrel cleaning, and tried different ammo. All the ammo I have shot has been 55 grain, but to me it doesn't seem like the type of issue to cause this big of groups.
I really don't think this is a shooter issue as I've shot some great groups with alot of other rifles.
I understand the design was bought and is still produced by Bushmaster. I contacted them and they no longer work on these rifles. Alot of the parts are gun specific and won't interchange w/ most AR's. There doesn't appear to be any parts available other than finding another rifle. The rifle functions and shoots great and at 4#'s it's very light and unique.
Bushmaster suggested that I could buy another bolt and barrel and try them. The bolt has rounded lugs on it and is slightly different than most Ar's. The barrel is think w/ fluting and I believe 1/9 twist chambered in 556.
Everything is tight and in good shape and I can't see where the gun has been shot alot. The receivers lock up tight.
One idea I had was to remove the barrel and retork it into place. Not sure what this would accomplish, but wanted to ask.