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The HK21E Belt Fed Machine Gun
Caliber 7.62 x 51 NATO


Jim Schatz of HK demonstrates the belt pulling ability of the HK21E.  Don't try this at home!


The HK21E is HKs mainstay belt fed machine gun.  It has undergone several product improvements over the years.  It began life in 1961 as the HK21, then in 1974, the HK21A1, and now the HK21E, as such in production since the early 80s..  "E" stands simply for Export.  Using the same roller locked bolt as most of the other HK automatic firearms, the HK21E features a quick change barrel that can be pulled and replaced in seconds without gloves.  The gun also features a bolt forward assist, fully adjustable sights to 1200 meters, an adjustable bipod, carrying handle and three shot burst trigger group.  It can be mounted on a tripod, as seen below.  The belt box in the photograph below holds 100 rounds of belted .308 (7.62 x 51) ammunition.  This gun in its latest iteration, improved over the HK21 and HK21A1, has been in series production since 1976.

Caliber Cyclic Rate Mag Capacity Modes of Fire Width (in/mm) Height (in/mm) Weight (lb/kg) bbl. length (in/mm) Overall
Length (in.mm)
7.62 x 51 850 Belt/20/50 S/3/F 5.24 8.26 20.50 17.72/22.05 44.88
7.62 x 51 850 Belt/20/50 S/3/F 133 210 9.3 450/560 1140

A rare variant of the HK21 tripod with shock absorbing mount.  The HK21 tripod is one of the rarest accessories in private hands in America, with only a few known specimens.  I don't believe that there are any of these particular shock absorbing mounts in private hands in America.  The version below is the more common version.  In German these are called Feldlafetten, or field mounts.

HK21E on more commonly seen tripod, Model 1102.  This tripod, though rare, is in possession in private hands in America.  It has the ability to accept the periscope optic that the firer can use to sight targets without head exposure.


The HK21E has a magazine adapter kit that installs easily in a short amount of time.  Doing this makes the designation of the gun HK11E.  Nothing changes on the gun, but the internal dating code of Heckler & Koch makes this the correct designation.  This is one of those accessories where you wonder what wisdom there is going from a belt to a 20 round box.  The overriding consideration might be weight, but the bulk of the weight is in the gun, not the belt.


First cousin to the HK21E is the HK11E when the belt fed machine gun is fitted with the accessory box magazine adapter.

Left side view.  Shown is the 17.7 inch barrel and magazine adaptor.  Standard G3 magazines can now be used.


Conversion kits used to change the HK21E to the HK11E and back.  Belt feed unit and bolt carrier assembly are on the left, and the box feed conversion is on the right.  A different strength mainspring is also necessary.


Barrel for firing blank cartridges that allows the gun to cycle normally


HK21E with 4X telescopic sight, and three round burst trigger group.  This is the only trigger group offered on 21s exported to the U.S.  The "E" in HK21E stands for "Export."

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