90 mm Gun M1/M2/M3

The 90 mm Gun M1/M2/M3 served as a primary heavy American anti-aircraft and anti-tank gun, playing a role similar to the renowned German 88 mm gun. It was 90 mm (3.5 in) in caliber, and had a 4.60 m (15 ft) barrel, 53 calibers in length. It was capable of firing a 90×600 mm R shell 17,823 m (58,474 ft) horizontally, or a maximum altitude of 10,380 m (34,060 ft).

The 90 mm Gun was the US's primary anti-aircraft gun from just prior to the opening of World War II into the 1950s, when most anti-aircraft artillery was replaced by guided missile systems. As a tank gun, it was the main weapon of the M36 tank destroyer and M26 Pershing tank, as well as a number of post-war tanks. It was briefly deployed 1943-46 as a coast defense weapon with the United States Army Coast Artillery Corps.

Country Name Origin Year
United States of America 1940
Country Name Operational Year Retirement Year
United States of America 1940 View

Prior to World War II, the primary US anti-aircraft gun was the 3-inch M1918 gun (76.2 mm L/50), a widely used caliber for this class of weapon. Similar weapons were in British, Soviet and other arsenals. There had been several upgrades to the weapon over its history, including the experimental T8 and T9 versions developed in the early 1930s that were intended to enter service later in the decade.

However the US Army became interested in a much more capable weapon instead, and on June 9, 1938 it issued a development contract calling for two new guns, one of 90 mm which it felt was the largest possible size that was still capable of being manually loaded at high elevations, and another, using assisted loading, of 120 mm caliber. The new design seemed so much better than developments of the older 3-inch that work on the 3-inch T9 was canceled in 1938 just as it became production-ready. By 1940 the second development of the 90 mm design, the T2, was standardized as the 90 mm M1, while its larger cousin became the 120 mm M1 gun.

A few hundred M1s were completed when several improvements were added to produce the 90 mm M1A1, which entered production in late 1940 and was accepted as the standard on May 22, 1941. The M1A1 included an improved mount and spring-rammer on the breech, with the result that firing rates went up to 20 rounds per minute. Several thousand were available when the US entered the war, and the M1A1 was their standard anti-aircraft gun for the rest of the conflict. Production rates continued to improve, topping out in the low thousands per month.

Like the German 88, and the British QF 3.7 inch AA gun, the M1A1 found itself facing tanks in combat, but unlike the others it could not be depressed to fire against them. On September 11, 1942 the Army issued specifications for a new mount to allow it to be used in this role, which resulted in the 90 mm M2, introducing yet another new mount that could be depressed to 10 degrees below the horizontal and featured a new electrically-assisted rammer. It became the standard weapon from May 13, 1943.

Type Anti-Aircraft gun
Place of origin United States
Service history
In service 1940–1950s
Used by United States,
Canada,
Republic of China,
Brazil
Wars World War II,
Korean War
Specifications
Weight Total: 8,618 kg (18,999 lb)
Barrel: 1,109 kg (2,445 lb)
Length 4.73 m (15 ft 6 in)
Barrel length 4.60 m (15 ft) L/53
Width 4.16 m (13 ft 9 in)
Height 3.07 m (10 ft)
Shell 90×600 mm R
Caliber 90 mm (3.5 in)
Carriage mobile
Elevation -5º to +80º
Traverse 360 degrees
Rate of fire 25 rounds per minute (maximum)
Muzzle velocity 823 m/s (2,700 ft/s)
Maximum firing range Maximum horizontal: 17,823 m (58,474 ft)
Maximum ceiling: 10,380 m (34,060 ft) (limited by 30 second fuse)

End notes