The Cross Machine Tool Ultra Precision Upper Receiver Part# UPUR-1A is the perfect Mate to your UHP-15 lower receiver or would also be a great match with any Mil-Spec lower. The UPUR-1A is machined from Billet 7075 T6 Aluminum unlike the more commonly used 6061. Using the 7075 T6 aluminum gives the UPUR-1A a 65% increase in strength & rigidity over 6061 aluminum receivers. The UPUR-1A is machined on a 5 Axis machining Center to reduce the number of operations/setups required to complete. This machining process allows the highest possible accuracy to be obtained over the traditional 3 or 4 Axis machining method. The UPUR-1A is designed for increased function, performance & to provide an advanced modern appearance & feel to the AR15 platform weapon system. The UPUR-1A has the same features as the original UPUR-1 with the addition of an enlarged ejection port opening for 458 SOCOM Rifle Builds Features- 5 axis machined from 7075 T6 billet M4 feed ramps Engraved “T” numbers 1913 picatinny Rail flat top Mil Spec Type III class II hard coat anodized Black Shell deflector Forward Assist machined into receiver Dust cover port machined into receiver Increased wall thickness for added rigidity Compatible with Mil spec parts Compatible with most aftermarket handguard/rail systems Enlarged ejection port compatible with 458 SOCOM Lifetime warranty against manufacture defects Comes stripped without dust cover & forward assist assembly Compatible with "Tactical Link" Enhanced Battery Assist Lever