FN SRP G2 AR-15 Complete Upper Receiver 5.56x45mm NATO with 16 inch barrel. Lightweight MIL-SPEC upper with extended handguard for maximum top rail space. Chrome-lined barrel with pinned low-profile gas block. Chambered in 5.56 NATO and designed for AR-15 platforms. Includes MIL-SPEC upper components and is ready for assembly with other lower parts.