L64 Assault Rifle

The L64 was an intermediate calibre British bullpup layout assault rifle developed in the 1970s. At one time it was known as the 4.85 Individual Weapon.

The British had considered bullpup designs with intermediate calibre rounds in the 1950s; though one, the EM-2, had been on the point of being introduced it had been dropped when a full calibre round was adopted as the NATO standard.

In the 1970s, the British Army started looking again at new assault rifle designs, using lighter rounds than the then standard-issue 7.62 mm L1A1 SLR used. Their research suggested that a slimmer bullet of the same general weight as the M16's 5.56x45 mm (.223") would result in the same ability to be fired in fully automatic mode, while having much better penetration and ballistics. The result was the .190-inch (4.85 mm) round fitted in "necked down" but otherwise standard 5.56 mm cartridges from the M16.

The Royal Small Arms Factory developed a rifle to fire the new round. The new L64/65 "Individual Weapon" was outwardly similar to the earlier EM-2, but adopted a firing mechanism very similar to ArmaLite's latest AR-18 design. The first examples were available in 1972.

By 1976, NATO was ready to standardize on a small calibre round. The testing of the various rounds head-to-head started in 1977. The British round out-performed the standard US 5.56 mm. However Fabrique Nationale's entry based on the 5.56 mm, the "SS-109" performed as well as the British cartridge. In the end it was selected largely due to its similarity with existing US ammunition.

The weapon was later developed into the SA80 family of weapons which entered service with the UK.

L64 Individual Weapon
Type	Assault rifle / Light machine gun
Place of origin	United Kingdom
Service history
In service	1960s-1980s
Used by	British Army
Wars	Cold War
Production history
Designed	1960s/70s
Manufacturer	RSAF
Produced	1964-1970
Number built	N/A
Variants	XL64, XL65, XL70
Specifications
Weight	8 lb 8 oz (3.89l kg) (unloaded)
Length	770 mm
Cartridge	4.85mm SAA (.191 in) 55-grain
Caliber	.191
Barrels	20.4 in (518 mm) 4 grooves, right-hand twist
Action	Gas
Muzzle velocity	2,952 f/s (906 m/s)
Feed system	20 round box magazine
Sights	SUSAT (SUIT)