Spike's Tactical Jack-10 upper and lower receiver set is CNC-machined from 7075-T6 billet aluminum. It has a heavily flared magwell, oversized integrated trigger guard, and a Black Type III Hardcoat Anodized metal finish. It is suitable for .308, 6.5 Creedmoor, or 338 Federal. The Jack-10 is compatible with any AR-style 308 barrel/bolt carrier group; SR25 or DPMS barrel nut; SR25, DPMS high, Armalite AR-10 handguard height; any SR25 or DPMS magazine; and any AR-compatible trigger group.