gun did'nt miss a beat, put a armalite 1 piece scope mount on her, and a redfield 6x18... and 300 rounds of sellier & bellot 55gr brass case boxer to the range...left the 30 round mags at home... i did use a bushmaster 10 round aluminum, 10 round steel olympic that came with the gun... and a thermold 20 round mag... i then proceed to sight in, took 5 shots to get on paper at 50 yds... then adjusted and kept 5 round groups into 1 inch fairly easy... then went to the 100 yrd range and proceeded to shoot 2-3 inch groups consistently... the gun is very obiously capable of shooting MOA or SUB, but the trigger was pulling me a little, besides i'm not exactly a crack shot with the ar15 yet... but i'm practicing now that i have this gun..... I WILL say this... the upper and lower, are as perfect as a rifle i have ever seen.... VERY tight specs, no side to side or up down play what-so-ever... all three mags tested operated flawlessly, no stoppages, and bolt held back on every last shot... just perfect with all 300 rounds... was laying rifle on a 4X4 block of wood... want to put a bipod on next... great gun for $659 delivered...better than guns that may cost 2X as much.... trigger need a little work, or maybe just break in... ...