(#6) No FFL required. This BCA AR-10 complete 308 rifle length upper has a 20” 416R Stainless Steel Heavy Barrel, and features 1:10 twist with a rifle length gas system. It includes 15” M-Lok split rail, an M4 flat top billet upper receiver, a BCA AR10 bolt carrier group, a flash hider, and a right side charging (Gen2) handle. This 308 upper is compatible with 1st Gen DPMS low profile receiver. 5/8x24 thread pitch, non-fluted, AR-10 feedramp, .750 gas block system. Billet receiver. E9310 bolt material.