I have the bull barrel DPMS .22lr upper. I have been very happy with it. Bought it from Element Arms in Becker Minnesota. I have had it about 2 or 3 months. It is 1" @ 50 yards and very reliable. Easy to disassemble for cleaning. Scope holds zero when switch barrels from .223 to .22lr I have had a few light strikes that resulted in failure to fire. I have tried cci-mini mag, blazer and Federal. All seem to cycle fine and all seem to have the same light strike issue. About one round out of 100 and I will try some other ammunition to see if its ammo related or firing pin/striker related. It uses Black Dog mags and have used the 10, 15 and 25 round magazines. I really like the feel and operation of this. It has a operating discharge dust shield. depending on the magazine used it has last shot hold open, but will close bolt as soon as the magazine is removed. Forward assist is cosmetic. The front forearm is threaded onto an aluminum collar and is not tight enough from the factory. Easy fix, tighten securely or use blue lock tight. Well built.
David