Feature Details
Platform: AR-15 based, proprietary to HK
Caliber: 5.56×45mm NATO (.223 Rem compatible)
Barrel: Cold hammer-forged, 1:7″ twist, chrome-lined
Gas System: Short-stroke gas piston system (non-direct impingement)
Material: High-grade steel and aircraft aluminum
Rail System: Free-floating quad rail (proprietary design with HKey interface)
Compatibility: Best used with HK lowers, but can fit mil-spec AR-15 lowers with some caveats
Bolt Carrier Group (BCG): Included, proprietary HK design, chrome-lined, enhanced reliability
Charging Handle Standard AR-style, often upgraded by users
