3-inch/50-caliber gun

3-inch/50 caliber gun (Mk 22)
Mark 22 3"/50 cal gun
Type	Naval gun
Place of origin	United States
Service history
In service	1900–1990 (US Navy)
Used by	US Navy
Production history
Designed	Mark 2: 1898 * Mark 10: 1915 * Mark 22: 1944
Produced	1900–1948
Variants	Marks 2, 3, 5, 6, 8, 10, 17, 18, 19, 20, 21, and 22
Specifications
Mass	Mark 2: 2,086 pounds (946 kg) (with breech) Mark 21: 1,760 pounds (800 kg)
Length	Mark 2: 153.8 inches (3.91 m) Mark 21: 159.7 inches (4.06 m)
Barrel length	Mark 2: 150 inches (380 cm) bore (50 calibres) Mark 21: 150.3 inches (382 cm) bore (50 calibres)
Shell	complete round: 24 lb (11 kg); projectile weight: 13 lb (5.9 kg) projectile types: AP, AA (with VT proximity fuze), HE, Illumination[1]
Caliber	3-inch (76 mm)
Elevation	Pedestal Mount: -10° to +15° AA Mount: -10° to +85°
Traverse	360°
Rate of fire	Mark 2: 15 – 20 rounds per minute Mark 22: 45 – 50 rounds per minute with autoloader[2]
Muzzle velocity	2,700 ft/s (820 m/s)
Maximum firing range	14,600 yd (13,400 m) at 43° elevation 30,400 ft (9,300 m) AA ceiling
Sights	Peep-site and Optical telescope

The 3-inch/50-caliber gun (spoken "three-inch fifty-caliber") in United States naval gun terminology indicates the gun fired a projectile 3 inches (76 mm) in diameter, and the barrel was 50 calibers long (barrel length is 3 in × 50 = 150 in or 3.8 m). Different guns (identified by Mark numbers) of this caliber were used by the U.S. Navy and U.S. Coast Guard from 1900 through to 1990 on a variety of combatant and transport ship classes.^[3]

The gun is still in use with the Spanish Navy on Serviola-class patrol boats.