Re: Recent accuracy issues?
Your problems sound alot like a scope that has gone bad, or a mounting system that is loose, worn, or broken. My first suspect would be the scope. However, just to be cautious, I would check:
1. Muzzle device to insure it is tight and not wobbling or has come out of alignment.
2. Gas block to make sure it hasn't suddenly started wobbling around.
3. If your barrel was installed properly, the gas tube should keep it locked into position, but it wouldn't hurt to check to make sure.
4. Insure that the forend is tight. Depending on the method used to secure the forend, if it has come loose, the wobble can affect things.
5. Check underneath your muzzle device to see if you have alot of carbon buildup that causes a false crown. If you have a buildup of carbon, that can really wreak havoc with how the bullet's base gets pushed as it exits the bore.
Obviously, if there is a buildup, carefully clean it off to get back to the fresh clean crown.
6. As you have probably eliminated the scope as the problem, check your mounting system starting with the base. Make sure that the base is tight, then that the rings are tight. Insure that the rings hold the scope tightly enough. If any one of those three aren't tight, problems develop. Remember that the rings should be pushed to the front of the rail when mounting as that is where recoil will seek to drive them anyhow.
7. Lastly, suspect the barrel. It is always possible that you just have a bad barrel. If that is the case, and DPMS built the rifle, return the rifle to them to have it fixed.
Many manufacturers (some much more than others) will seek to either blame something you did, your ammo, or anything other than admitting that perhaps they had a manufacturing glitch. That always struck me as odd as simple logic says that if you make enough of anything, eventually something will go wrong. I believe that the positive customer good will of admitting to an occasional problem and promptly fixing it would far outweigh telling the customer it is their fault, or saying something that comes across as "We never make mistakes because we are perfect", so it has to be your fault.
I had a manufacturer blame a magazine for problems with extraction, over pressure and other items that were clearly the result of a short throat. When I could extract unfired rounds, you could see the lands engraved onto the bullets that weren't retained in the bore. A gunsmith at the range even verified what the issue was. I returned the rifle, and it got the throat fixed, but I was told that it was a bad magazine. Yeah, sure....
It seemed only reasonable that if you chamber and throat 10,000 rifles, eventually one will get short throated, or have some issue with the chamber. To blame a magazine was embarrassingly illogical for that company.