My buddy used a 16" BM with usgi mags.I cant tell you what kind of rifle i shot cause i think Bushmaster will get pissed if they find out i used one of their DCM rifles to hose multiple targets at 3 yds ;). I was the only guy there with a 20" gun that weighed 14 lbs though.Another guy tried it out of a DPMS bull barrel after the match for the heck of it, and got the same results.I wish the local gun crook,I mean store, was still selling the South African.Oh well,last uspsa rifle match of the year,we'll worry about it next year.