1000 rounds so far, performance has been flawless. 2" groups for the first 200 rounds or so gradually getting tighter. Now grouping around 1" or less with a Leupold 6x and Hornady match ammo. Every mag I have tried has worked flawlessly(though some fit pretty tight in the mag well). The BUIS work well. Did some speed drills with an Eotech on it, nice and fast. A little barrel heavy, but not terrible. The ACE stock is fantastic. The rail is great for switching between a bipod and KAC grip. Everything I was looking for in an AR. Thanks Bushmaster!