Heckler & Koch HK21
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The HK 21 is a belt-fed light machine gun using the 7.62 x 51 mm NATO cartridge manufactured by the German arms manufacturer Heckler & Koch. The gun may be fired at single shot or full automatic. The selector lever is above the pistol-grip and the trigger mechanism, disconnector and automatic sear are the same as those used in the G3 rifle. The HK 21 may be used from its integral bipod or from a tripod mount.
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[edit] Operation
The method of operation of the HK 21 is the same as that used in the G3 rifle, employing a two-part breech block and delay rollers. The delayed blowback system, with a fluted chamber for easy cartridge movement, operates from the closed bolt position with a round in the chamber when the gun is ready to fire. Ammunition for HK 21 usually is carried in disintegrating link belts and the gun will function using either the German DM 60 belt, the US M13 belt, or the French belt. However, the continuous link belt DM 1 can also be used if required. Furthermore, by changing the barrel, the belt feed plate and the bolt, the gun can be converted to firing the 5.56 x 45 mm or the 7.62 x 39 mm cartridge.
The utility of the weapon is further increased by inserting a magazine adaptor in place of the feed mechanism. This takes any of the proprietary Heckler and Koch 7.62 mm box magazines intended for the G3 rifle or the HK 11 automatic rifle. If required, the belt feed unit can be withdrawn altogether and replaced with a magazine unit which fits into the receiver and is held by two locking pins. The unit allows the use of the HK 11's 20-round box magazine or 80-round double-lobed drum magazine.
[edit] Manufacture
Both the HK 21 and HK 21A1 models are currently discontinued by Heckler und Koch, but are still manufactured under licence in Mexico, Portugal and Greece. Currently, HK manufactures two models of improved original design: HK 21E in 7.62 × 51 mm NATO and HK 23E in 5.56 x 45 mm NATO (.223Rem). HK 23E is similar to HK 21E in every respect excluding the chambering and barrel length. The most major updates over the 21A1 are: slightly lengthened receiver; fire control block with semi-auto, 3-round bursts and full-auto modes of fire; Special bolt closing device for quiet bolt closure; re-design of the belt-feeding mechanism: the belt feed mechanism smoothly feeds the belted ammunition in two stages, during the rearward and the forward movement of the bolt. The ability to use G3 or STANAG (for HK 23E) box or drum magazines is available with optional feed module kit (see picture) that consist of the bolt, recoil spring and belt feed module or magazine well. The HK 21E has rear drum sight graduated up to 1200 meters and up to 1000 meters for HK 23E; both sights are adjustable for windage.
[edit] HK21E
The HK21E mainstay uses a roller locked bolt, fires a 7.62 × 51 mm caliber round. It has belt feeding capabilities and fills the role of a squad automatic weapon. Most versions of the HK21E had three-round burst trigger groups, so a three-round burst mode was available. The HK21E started as the HK21, a simple machine gun using the same caliber rounds. Then came the HK21A1, which featured some other minor modifications. The E in HK21E stands simply for Export. It was tuned until it fit American import standards before it was imported.
[edit] Service
- The HK 21 is in service in Portugal and some African and Southeast Asian countries.
- The HK 21A1 is in service with Greece.
- The HK 21E is in service in Mexico and other countries and is currently manufactured by HK in Germany for export.
In the Bundeswehr the HK21 is called G8, although it is only used by specialized and special forces. The German KSK uses the HK21 additionally to the new standard machine gun MG4.
[edit] External links
[1]"H&K HK21 / HK21A1 / HK21E / HK23E." Nazarian's Gun's Recognition Guids. 2006.
