LM8MWS monolithic upper receiver for large caliber rifle platforms. Created with smooth sides for better weapon ergonomics. The 3, 6 and 9 o’clock rails have locating lugs and screw holes. The locating lugs take the recoil of attached accessories while the screw holes hold the accessory or rail to the weapon. Utilizes two locking lugs to secure/remove any larger caliber LMT barrel. This includes: 7.62×51 NATO, .243 Winchester, .260 Remington, 6.5 Creedmoor, 7mm-08 Remington, and .338 Federal. Barrel not included.