The HK21A1 served as an evolution to the original HK21. Each HK21A1 rifle is built from factory HK German demilled rifles and German receivers for an authentic German build. Obsidian Ordnance HK21A1’s include a brand new, genuine HK feed mechanism, M13 sprocket, and matching M13 bolt head.

Rifles ship with a 50-round belt but can also utilize the 100-round drum (requires drum hanger) as seen in pictures.