In 1968 Heckler & Koch launched the HK33, chambered in 5.56x45mm, to compete with Colt’s AR-15/M16. The HK33, and later HK53, used the same roller-delayed blowback action developed for the G3 in the mid 1950s. However, few major contracts were forthcoming with the German military opting to continue using the 7.62x51mm G3.
Due to the modularity of the HK33′s design users could replace the butt of the standard rifle with a collapsible telescopic metal stock. H&K also subsequently designed a carbine version of the full-length HK33, the HK33K with a telescopic metal stock and 12.7 inch barrel. In the mid-1970s H&K began development an even shorter version. The result was essentially an intermediate calibre submachine gun similar to the Colt Commando and the Soviet AKS-74U. H&K designated this new weapon the HK53, it used the same telescopic stock as the HK33K and MP5 and a cut down 11 inch barrel, the HK53 also utilised a polymer forearm similar to the MP5s.
Like the HK33, the HK53 fed from 25, 30 or 40 round box magazines. The weapon weighed just over 3kg (7lb), almost a 1 kg less than its parent rifle the HK33. Unlike the HK33, the HK53 has a four prong flash hider. A number of police forces and militaries adopted the HK53 for a variety of roles. Special forces units around the world including the British SAS, Royal Military Police Close Protection Unit and Royal Marines, designated the L101A1 in British service, who typically used it during close protection duties and operations involving close quarter battle.
As shown in various MoD Equipment Failure Reports dating from the early 1990s the HK53’s in British service suffered from repeated damage and failure of the carbines’ locking rollers. This issue arose when using a number of different ammunition types including brass cased blank ammunition (H&K recommend the use of their proprietary blank cartridges). Following a meeting between the Army Technical Support Agency’s Directorate of Engineering and H&K a new design for the locking pieces were developed. These changes “increased the roll of blowback force during the unlocking phase… in turn this will reduce the mean energy of the recoiling mass of breech block and carrier” this was intended to reduce bolt bounce. The Royal Military Police Close Protection Unit’s L101A1’s were also fitted with a new two stage buffer within a fixed stock.
Due to its short length the HK53 also found itself pressed into the port-firing weapon role. Designated the HK53 MICV in this role the foregrip and stock was removed and a specially designed endcap and a spent case bag could be attachment. During its service life the HK53 went through a series of changes to furniture mouldings, buttstock types and fire selector options. It remained in production into the early 2000s, when Heckler & Koch replaced the HK33 and HK53 with the G36 and G36K.
Technical Specifications (from 1987 H&K brochure):
Length (with stock extended): 76.5cm (30in)
Weight (collapsible stock, unloaded): 3.35kg (7.4lb)
Barrel Length: 22.5cm (8.5in)
Action: Roller delayed blowback
Feed: 25, 30, or 40-round box magazine
Cyclic Rate: approx. 700 rpm
The World’s Assault Rifles, G.P. Johnston & T.B. Nelson, (2010)
Heckler & Koch HK33 & HK53 manual (source)
HK53 factory colour brochure, 1987, (via Small Arms Review Reference Library)
Itemised list of L101A1’s which suffered damaged locking rollers, MoD Equipment Failure Report, 15 Nov. 1994, (via Small Arms Review Reference Library)
Army Technical Support Agency report on receiver damage to HK53 and G3 rifles, 1996,(via Small Arms Review Reference Library)
Please do not reproduce photographs taken by Matthew Moss without permission or credit. ©The Armourer’s Bench 2018.