Technical Specifications

Type	General-purpose machine gun (HK21) · Light machine gun (HK23) · Heavy machine gun (HK25)
Country of origin	West Germany
Manufacturer	Heckler & Koch · Fábrica de Braço de Prata · SEDENA
Designer	Heckler & Koch
Designed	1961
Produced	1961–1990
In service	1961–present
Used by	See Users
Variants	See Variants
Weight	HK21: · HK21A1: · HK11A1: · HK21E: · HK11E: · HK23E: · HK13E: · HK25:
Length	HK21: · HK21A1, HK11A1, HK11E, HK23E, HK13E: · HK21E: · HK25:
Barrel length	HK21, HK21A1, HK11A1, HK11E, HK23E, HK13E: · HK21E: · HK25:
Cartridge	HK21, HK21A1, HK11A1, HK21E, HK11E: 7.62×51mm NATO · HK23E, HK13E: 5.56×45mm NATO · HK25: 12.7×99mm NATO
Action	Roller-delayed blowback, closed bolt
Feed	M13, DM6, DM1 ammunition belt, 20-round detachable box or 50-round drum magazine (from the G3). An 80-round drum magazine or even a 100-round drum magazine was also available (No longer manufactured)
Muzzle velocity	HK21, HK21A1, HK11A1, HK11E: · HK21E: · HK23E, HK13E: (using the SS109 cartridge) · HK25:
Rate of fire	HK21, HK21A1: 900 rounds/min · HK11A1, HK21E, HK11E: 800 rounds/min · HK23E, HK13E: 750 rounds/min · HK25: 450 rounds/min
Range	sight adjustments