Originally designed as an oiled cartridge for the HS 404, the 20x110mm was redesigned by the British to eliminate the need for oiling. Possessing a 15 to 20% higher muzzle velocity than the Oerlikon S cartridge it closely resembled, the 20x110mm initially used ball projectiles in British service, before standardisation on HE/I and AP/I ammunition.
The standard 20 x 110 cartridge had a rim and body diameter of 24.8 mm. There were two HE projectile types - a 130 gram round used in most versions, which were percussion primed, and a 102 gram round for the electrically primed US M24 weapon. [N 2]
- ↑ The Soviet Union used a 20x99R as it's standard 20mm cartridge. 
- ↑ The United States Navy used a slighter larger version of the cartridge. With a rim diameter of 29.5 mm, body diameter of 29.3 mm, weight of 110 grams and muzzle velocity of 1,010 m/sec, this cartridge was primarily used post war by the USN Mk 12 weapon.
- ↑ International Ammunition Association
- ↑ 2.0 2.1 Williams, Anthony G. Rapid Fire - The Development of Automatic Cannon, Heavy Machine Guns and their Ammunition for Armies, Navies and Air Forces. Airlife Publishing. 2000. ISBN 1-84037-122-6 Page 226
- ↑ Williams, Anthony G. Page 73
- ↑ Williams, Anthony G. Page 185