Have a DPMS and have had issues. Had a brand new car and had issues. Does not matter as all machines falter at times. The DPMS was touchy from day one. Kept wiping out the rings in the firing pin carrier. Replaced some of the components and it now runs great. My Colt has never really missed a beat with an occasional FTF when using reloads. That was after god now's how many thousands of rounds. New firing pin and a few misc. bits and it runs like a race horse. Traded the Colt to a buddy and he has used it for an ammo hose....no issues. My M&P runs great but one day it will burp or fart and I will have to put some parts in it as well. Never had a bushy but friends do and they love them. A part here or there..(I will work on them for beer) and off they go. They are machines, machines fail, people miss-treat machines. Vicious circle. Enjoy you AR's...What a country