I have a 16" lightweight barrel on a Colt lower. Good gun, and I can say very reliable after 2000 rounds with no FTFs or FTEs. Gets about 3-4 MOA with no optics and no real benching. (just rested it over a rolled up blanket last time I grouped it) I know you probably would be more interested in accuracy, but I haven't tried to really wring out the accuracy since it's a light contour barrel - sorry.