Originally manufactured in Germany as a HK91 semi-automatic rifle, this firearm has been given two rounds of significant upgrades. The first set of upgrades was performed by Vollmer Manufacturing (so marked on the right side of the belt mechanism), which converted the 91 to the HK21 pattern, integrating a belt feed mechanism, ventilated handguard with bipod rails, and reconfiguring the receiver to accept quick-detach heavy barrels (one included). The second round of upgrades was performed by Fleming Firearms (so marked on the right side of the receiver, hidden by the trigger group) which outfitted the gun with a fully functional machine gun trigger pack installed in a "S/E/F" marked housing. Taken in total, these upgrades result in the closest possible representative of the original German-designed squad automatic weapon. Post front and "2-12" adjustable peep rear sights, with a folding bipod and vertical foregrip installed on the forearm, the "HK21" marking on the left side above the belt mechanism, and the original model designation on the right. Fitted with a textured right handed pistol grip and a "club foot" style fixed buttstock.