The BILLet-AR10 upper receiver has a precise bolt raceway for smoother chambering and more rigid receiver walls to reduce firing flex. The BILLet-AR lower receiver has been enhanced with an oversize magazine well for smooth reloads and an integral trigger guard for gloved use and added lower receiver strength. Features- Picatinny top rail; shell deflector; M4-style extended feed ramps for excellent reliability with a wide variety of calibers; undersize bolt raceway for smoother chambering, improved feeding and enhanced recoil dynamics; smooth side profile without forward assist for maximum accuracy potential; oversize, EDM-cut magazine well for fast reloads; precision threaded receiver and reamed pin holes and hex Screw Bolt Catch retention. Hand prepped for a flawless surface finish.