L21A1 (30 mm)

The 30 mm L21A1 on the Warrior gun mantlet.

Description

The 30 mm L21A1, also known as the RARDEN, is a British autocannon used on their armoured fighting vehicles. Currently, the only vehicle using the L21A1 cannon is the FV510 Warrior.

With its APDS round, the L21A1 has one of the higher penetrating rounds for an autocannon for a ground vehicle in the game that can take out most other light tanks with ease. However, the trade-off is a lower firing rate and restricted magazine size of 6 rounds.

Vehicles equipped with this weapon

• Warrior
• Fox

General info

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Available ammunition

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Comparison with analogues

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Usage in battles

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Pros and cons

Pros:

• High-penetrating APDS round available for its calibre size
• APDS belt is homogeneous, guaranteeing a APDS round each shot compared to mixed belt compositions

Cons:

• 6 round magazine requires careful shot placements to make most use of the available rounds
• Low rate of fire
• Relatively high recoil when firing compared to other autocannons

History

Considerations for a new vehicle-mounted weapon for the infantry took into account that a Soviet invasion of Europe would have the Soviet armoured forces tie down most of NATO armoured assets. In this event, NATO infantry would have minimal armour support against the Soviet's mechanized infantry, which are usually supported by armoured personnel carriers or infantry fighting vehicles in the form of BTRs or BMPs. As such, a vehicle-mounted weapon capable of defeating these Soviet vehicles from 1,000 m away was desired to force the infantry to disembark and allow effective mortar and artillery fire to decimate them. Settling on a high-velocity autocannon weapon type for the role, it was found that current autocannons in service did not meet the British requirements for a vehicle-mounted armament. The British decided to pursue a path of producing a completely new 30 mm autocannon to fit their needs. This task was taken up between the Royal Armament Research and Development Establishment (RARDE) and the Royal Small Arms Factory at Enfield. Norman Brint of the Royal Small Arms Factory became the cannon's main designer.

A Warrior IFV from the Mercian Regiment with its L21A1 RARDEN.

The 30 mm autocannon developed was desired to have a sufficient anti-armour capability to defeat a Soviet APC from any angle up to 1,000 m away, with an ability to penetrate the side armour of Soviet main battle tanks as well. The autocannon should also be able to provide effective fire on soft targets and be able to deter low-flying aircraft such as helicopters. Additionally, the gun is to be reliable, accurate, lightweight, and be able to be mounted on a large variety of vehicles. These are tough specifications under the considerations that an effective vehicle-mounted cannon requires a low trunnion pull (recoil force) and a short inboard length (recoil length). To account for this, the weapon would have a low rate of fire and a long recoil mechanism, which effectively reduced the trunnion pull to 3,000 ft-lb (~4067 J), which is halved compared to other 30 mm autocannons of the time. The inboard length is reduced to a maximum of 9 in. (~23 cm), due in part with the absence of a ramming breech block and its associated return spring, as well as the loading and recoil mechanism that allowed the inboard length to load the 11.25 in. (~28.6 cm) round without issue.

Ammunition for the cannon are derived from the Hispano-Suiza 831L, with a new APDS ammunition was developed by RARDE for the armour-pericing role. The use of aluminum alloy in the gun body and high quality steel in the barrel kept the weapon lightweight (the barrel itself was only 54 lb. (~24 kg)). Barrel dampeners, as well as the low fire rate, help prevent barrel vibrations from affecting gun accuracy. The weapon, known as the 30 mm Gun L21E2 during development, was standardized in the British military as the L21A1. The weapon was also given the name RARDEN, the name derived from its designers ("Royal Armament, Research and Development Establishment" and "Enfield").

The L21A1 RARDEN would see use on the Fox armoured car, the Warrior IFV, and the Scimitar reconnaissance vehicle. The weapon would undergo an upgrade in the 1980s into the L21A2, which featured a redesigned barrel among other minor improvements.

Media

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See also

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External links

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Citations

Bibliography

• Hobart, Major F.W.A. "The RARDEN Cannon". Armor, January-February 1974, pp. 18–24. (Online Archive) (Archive.org copy)
• Tobin, Edmund. "Norman Brint designed the Rarden 30mm cannon at the Royal Small Arms Factory". East London and West Essex Guardian Series, Newsquest Media Group Ltd., 09 Apr. 2010, Website. Accessed 26 Mar. 2021. (Archive)
• WeaponSystems.net, "30mm Rarden". WeaponSystems.net, Website. Accessed 26 Mar. 2021 (Archive).

Britain tank cannons
30 mm	L21A1
40 mm	QF 2-pounder
47 mm	Ordnance QF 3-pounder
57 mm	6pdr OQF Mk.III · 6pdr OQF Mk.V
75 mm	OQF Mk.V
76 mm	OQF 3-inch Howitzer Mk I · OQF 3in 20cwt · QF 17-pounder
77 mm	OQF Mk.II
84 mm	20pdr OQF Mk.I
94 mm	28pdr OQF · 32pdr OQF · OQF Mk.II
95 mm	Howitzer, Tank No.1, Mk.I
105 mm	LRF · Royal Ordnance L7A1
120 mm	Ordnance QF Tk. L1A2 · Ordnance BL Tk. L11 · L11A5 · L30A1
165 mm	ORD BL 6.5in L9A1
183 mm	QF L4A1
	Foreign:
25 mm	M242 (USA)
37 mm	M5 (USA) · M6 (USA)
75 mm	M2 (USA) · M3 (USA)
84 mm	kan Strv 81 (Sweden)
105 mm	Sharir (Israel)
120 mm	Rh120 L/55 A1 (Germany)
125 mm	2A46M-5 (Russia)
155 mm	M185 (USA)
	South Africa
20 mm	GI-2
76 mm	GT-4
90 mm	GT-2
105 mm	GT-3 · GT-7 · GT-8
155 mm	G6 L/45