Subsystems / Cannon / Rarden


General Facts

  • TYPE

    United Kingdom

    L21 (UK service designation)

    Early 1960's

    Royal Small Arms Factory

    Early 1970's - late 1990's

    United Kingdom



    Fires powerful ammunition
    Can be mounted in small turrets
    No gasses entering crew compartment
    Cases ejected outside vehicle
    Low cyclic rate of fire
    Manually loaded by 3 round clips


The Rarden is a late Cold War era 30mm autocannon of UK origin. It was developed in the 1960's to arm the next generation of armored fighting vehicles. The 30mm caliber was chosen since it was expected that that in the 1970's Soviet armored vehicles would have an armor thicknes of up to 40mm RHA. The Rarden was design for vehicle use and unlike most autocannon it has not been in an anti-aircraft mount since it lacks the volume of fire for that role.


The Rarden is a magazine fed autocannon that uses a long recoil mechanism. The cases are ejected forwards and toxic fumes cannot enter the vehicle. The Rarden uses three round magazines that are inserted into the side. The barrel is long and thin and is made out of high strength steel. A vibration damper is fitted within the barrel sleeve to maintain the level of accuracy. The Rarden uses the 30x170mm round that was developed for the Oerlikon KCB (HS 831), but the ammunition types are not interchangeable since new KCB ammunition uses a steel case instead of a brass one.


The Rarden fires the 30x170mm round at a cyclic rate of fire of 90 rpm. The three round magazines are manually loaded with the feed mechanism accepting two magazines at the same time. The low volume of fire is offset by its high degree of accuracy. Waste of ammunition is also reduced. The 30mm ammunition range includes high explosive rounds and armor piercing discarding sabots that will pierce the armor of nearly any vehicle but tanks.


The Rarden is used on various vehicles of UK origin. The design allows it to be fitted into small vehicles such as the Fox 4x4 armored car and Scimitar tracked reconnaissance vehicle. The most common application is the Warrior mechanized infantry combat vehicle. The Rarden has not been used on foreign vehicles



Rarden: The Rarden is an autocannon of British origin. The service designation is L21A1. The L21A2 is an improved model introduced in the 1980's. It has a redesigned barrel and various minor improvements.

Caliber30x170mm KCB
MechanismLong recoil
Barrel2.44 m, rifled
Dimensions2.969 m long
Weight113 kg overall, 24.5 kg barrel
Feeding3 round box
Rate of fire90 rpm
Muzzle velocity1.070 m/s for HE, 1.175 m/s for APDS
RemarksFlash hider on muzzle

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