90 mm Gun M1

90 mm Gun M1
Name	90 mm Gun M1
Caption	A 90 mm Gun M1 on its M1A1 carriage.
Type	Anti-aircraft gun / Tank gun
Origin	United States
Service	1940–1960s
Used by	United States and others
Wars	World War II, Korean War
Designer	U.S. Army Ordnance Department
Design date	1938
Manufacturer	Watervliet Arsenal, others
Number	~7,800
Variants	M1A1, M2, M3
Weight	Travel: 19,000 lb (8,600 kg)
Length	16 ft 2 in (4.93 m)
Part length	Bore: 15 ft (4.6 m) (L/50)
Width	8 ft 6 in (2.59 m)
Height	Travel: 8 ft 6 in (2.59 m)
Cartridge	90×600mmR
Caliber	90 mm (3.54 in)
Action	Semi-automatic sliding wedge
Rate	15–20 rpm
Velocity	2,700 ft/s (823 m/s) (AP)
Range	AA: 34,000 ft (10,400 m)
Max range	18,000 yd (16,000 m) (horizontal)
Feed	Single-shot
Sights	M7 or M9 computing sight
Carriage	M1A1 four-wheeled split-trail
Elevation	-5° to +80°
Traverse	360°

90 mm Gun M1. The 90 mm Gun M1 was a powerful American heavy anti-aircraft and tank gun developed in the late 1930s. It became the primary heavy anti-aircraft weapon for the United States Army during World War II and was later adapted as the main armament for several iconic American tanks. The gun's design was influenced by contemporary European artillery and proved to be a versatile and effective weapon system.

Development and design

The development of the 90 mm Gun M1 was initiated by the U.S. Army Ordnance Department in 1938, driven by the need to replace the aging 3-inch Gun M1918. The design was heavily influenced by the successful German 8.8 cm Flak 18/36/37 and incorporated lessons from other contemporary weapons like the British QF 3.7-inch AA gun. The gun featured a long L/50 barrel, a semi-automatic sliding-wedge breech mechanism, and was mounted on a sophisticated four-wheeled M1A1 carriage that allowed for rapid 360-degree traverse. Key manufacturing facilities included the Watervliet Arsenal for the tubes and the Firestone Tire and Rubber Company for the carriages. Its fire control system, initially using the M7 director and later the M9 electronic director, represented a significant advancement in Anti-aircraft warfare technology for the period.

Service history

Entering service in 1940, the 90 mm Gun M1 quickly became the cornerstone of American heavy anti-aircraft defense. It was deployed extensively in all theaters of World War II, including the European Theater of Operations and the Pacific War, providing protection for vital installations, harbors, and field armies against high-altitude bombers. During the Korean War, it continued in its anti-aircraft role but saw increased use in a secondary ground support capacity against Korean People's Army fortifications. Its most famous service, however, was as the primary armament for American armored fighting vehicles, most notably the M36 tank destroyer and the M26 Pershing heavy tank, where it engaged enemy armor like the German Panther tank and Tiger I with considerable effect during battles such as the Battle of the Bulge.

Variants

The basic M1 design led to several important variants. The M1A1 introduced a muzzle brake to reduce recoil forces. The M2 was a redesign with a shorter chamber for fixed ammunition, intended primarily for tank use, and formed the basis for the M3 gun used in the M26 Pershing and M46 Patton. The M3 itself, with its distinctive bore evacuator, was the definitive tank gun variant. For anti-aircraft use, the system evolved with the T8 carriage, which led to the postwar M2 carriage used with the gun in its final AA configurations. These developments were paralleled by specialized ammunition types that enhanced the weapon's anti-tank capabilities throughout its service life.

Specifications

The 90 mm Gun M1 on its M1A1 carriage weighed approximately 19,000 pounds (8,600 kg) in traveling order. The barrel was 15 feet (4.6 meters) long, giving it a caliber length of L/50. The carriage provided an elevation range of -5 degrees to +80 degrees and full 360-degree traverse. It had a maximum horizontal range of about 18,000 yards (16,000 meters) and an effective anti-aircraft ceiling of 34,000 feet (10,400 meters). The gun's semi-automatic action enabled a sustained rate of fire of 15 to 20 rounds per minute. It was typically towed by heavy prime movers like the M4 High-Speed Tractor or M5 13-ton High-Speed Tractor.

Ammunition

The gun used separate-loading ammunition, consisting of a projectile and a brass cartridge case. A wide array of projectiles was developed. The initial M77 Armor-Piercing Capped (APC) round was supplemented by the more effective M82 Armor-Piercing High-Explosive (APHE). The T33 shot was a later, high-velocity solid armor-piercing round. For anti-aircraft use, the M71 and M91 time-fuzed high-explosive shells were standard. Other types included the M352 canister shot for anti-personnel use and practice rounds. The fixed ammunition used in the M2 and M3 tank gun variants offered improved handling and rate of fire within the confines of a Gun turret.

Operators

The primary operator was the United States Army, which used the gun through the Korean War. It was also supplied in significant numbers to Allied nations under programs like Lend-Lease. Major recipients included the United Kingdom, which deployed them for homeland air defense, and the Soviet Union, which received a quantity for evaluation and use. After World War II, the gun was widely exported to American allies, seeing service with the French Army during the First Indochina War and with the Republic of Korea Army. It remained in the inventories of several NATO countries and other nations like Japan and Taiwan into the 1960s before being replaced by missile systems like the MIM-23 Hawk.

Category:Anti-aircraft guns of the United States Category:World War II artillery of the United States Category:90 mm artillery