20 mm caliber
The 20 mm caliber is a common firearm bore diameter, typically used to distinguish smaller-caliber weapons, commonly called "guns", from larger-caliber "cannons" (e.g. machine gun vs. autocannon). All 20 mm cartridges have an outside projectile (bullet) diameter and barrel bore diameter of 0.787 inches (20.0 mm). These projectiles are typically 75 to 127 mm (3–5 in) long, cartridge cases are typically 75 to 152 mm (3–6 in) long, and most are shells, with an explosive payload and detonating fuze.
This article needs additional citations for verification. (April 2011)
Twenty-millimeter-caliber weapons are generally not used to target individual soldiers, but against targets such as vehicles, buildings, or aircraft.
Types of ammunition
- High explosive (HE)
- High explosive incendiary (HEI)
- Armour-piercing (AP)
- Semi-armor-piercing high explosive incendiary (SAPHEI)
- Armor-piercing discarding sabot (APDS)
- High-explosive fragmentary tracer (HEF-t)
- Penetrator with enhanced lateral effect (PELE)
- Target practice - inert projectile (i.e., PGU-27A/B). Used for training. (TP)
- Target practice tracer - inert projectile with tracer material in base for visual trajectory tracking (i.e., PGU-30A/B). (TP-T)
20 mm weapons
Each weapon is listed with its cartridge type appended.
|Weapon||Country of origin||Cartridge||Notes|
|Neopup PAW-20||South Africa||20×42 mm|
|Denel NTW-20||South Africa||20×82 mm Mauser|
|Anzio 20 mm rifle||United States||20×102 mm|
|M61 Vulcan||United States|
|M197 electric cannon||United States|
|M39 cannon||United States|
|ZVI PL-20 Plamen||Czech Republic|
|Metallic RT-20||Croatia||20×110 mm Hispano|
|Oerlikon KAA/KAB||Switzerland||20×128 mm||Formerly known as Oerlikon 204GK/5TG|
|Oerlikon KAD||Switzerland||20×139 mm||Formerly known as Hispano-Suiza HS.820|
|GIAT M693/20 mm modèle F2||France|
|Rheinmetall Rh 202||Germany|
|Denel Land Systems GI-2||South Africa|
Cartridge type indicates the diameter of projectile and the length of the cartridge that holds it; for example 20×102 mm is a 20 mm projectile in a 102 mm long case. Only rarely do two designers use the same case length, so this designation is usually definitive. Some cartridge types have additional letters or information about them listed.