Weighing 8.1 ounces, including forward assist and dust cover, the R-10 magnesium Upper Receiver is the lightest production LR308 upper with a forward assist on the market. For use with large caliber barrels like .308 Winchester/7.62x51mm NATO and 6.5 Creedmoor, amongst others, this upper is compatible with DPMS GEN 1 compatible lower receivers. The R-10 is a low profile upper and is designed with an enlarged ejection port to ensure reliability and a quick detach dust cover that can be removed without uninstalling the handguard and barrel nut. Protected with Tagnite and Cerakote, the R-10 Upper Receiver is the best choice for your ultra-light weight large caliber AR build.