Designed by Bill Wilson and the Wilson Combat design team to be the base for the ultimate precision tactical AR-15 rifle, the BILLet-AR upper receiver set is 100% machined in their Berryville, AR facility. The Wilson Combat BILLet-AR receiver was engineered from the ground up to address structural design weaknesses in standard USGI receivers and enhance overall tolerances. The BILLet-AR upper receiver has a precise bolt raceway for smoother chambering, more rigid receiver walls to reduce firing flex. Wilson Combat's extensive experience as a premier custom builder of AR-15 rifles will ensure your satisfaction with this next generation precision tactical shooting pla Mfg: Wilson Combat