90 mm Gun M1/M2/M3
|90 mm M1A1|
A 90 mm M1 at CFB Borden
|Place of origin||United States|
|Used by||United States,
|Wars||World War II,
|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)|
|Elevation||−5º to +80º|
|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)
The American 90 mm gun served as a primary heavy anti-aircraft and anti-tank gun, playing a role similar to the renowned German 88 mm gun. It 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.
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.
In anti-aircraft use the guns were normally operated in groups of four, controlled by the M7 or M9 Director or Kerrison Predictors. Radar direction was common, starting with the SCR-268 in 1941, which was not accurate enough to directly lay the guns, but provided accurate ranging throughout the engagement. For night-time use, a searchlight was slaved to the radar with a beam width set so that the target would be somewhere in the beam when it was turned on, at which point the engagement continued as in the day. In 1944 the system was dramatically upgraded with the addition of the SCR-584 microwave radar, which was accurate to about 0.06 degrees (1 mil) and provided automatic tracking as well. With the SCR-584, direction and range information was sent directly to the Bell Labs M3 Gun Data Computer, and M9 Director, which could direct and lay the guns automatically. All the crews had to do was load the guns. With the SCR-584 the 90 mm became arguably the best anti-aircraft weapon of the war.
Main Gun/Anti-tank developments
The M3 was also adapted as the main gun for various armored vehicles, starting with the experimental T7 which was accepted as the 90 mm M3. The test firing of the M3 took place on an M10 tank destroyer in early 1943. The M3 gun was used on the M36 tank destroyer, and the T26 (later, M26) Pershing tank. The M3 fired a M82 APC-T (tungsten) shot with a muzzle velocity of 2,650 feet per second. However, both the muzzle velocity of the standard M3 gun and the quality of the tungsten steel used in the M82 APC shot was inferior to the KwK 43 L/71 88mm main gun with tungsten AP shot used by German forces, with the result that the former's penetration fell far short of the projectile fired by the German 88mm used on the Tiger B (Tiger II or King Tiger) tank. As a result, U.S. ordnance provided some T26/M26 tank crews with the 90mm HVAP (high velocity, armor piercing) sub-caliber projectile with a muzzle velocity of 3,350 feet per second, or the T33 AP with a re-heat-treated projectile with ballistic windshield and a muzzle velocity of 2,800 feet per second.
Because the standard fifteen-and-a-half foot long M3 90mm main tank gun proved incapable of penetrating the heaviest frontal armor of the heaviest German tanks such as the Tiger B or King Tiger tanks, a number of improved versions of the M3 were developed, including the T14 which included a standard muzzle brake and the T15 series. The 21-foot long T15E1 90mm main gun fired AP T43 shot with an initial muzzle velocity of about 975 m (3,199 ft) per second, later increased to 1,143 m (3,750 ft) per second. Two M26A1E2 "Super Pershing" tanks were equipped with T15-series 90mm main guns in March 1945. One of these tanks, equipped with a 90mm caliber T15E1 high-velocity gun firing a 1,143 m (3,750 ft) AP shot made it to the European Theater of Operations and was assigned to the 3rd Armored Division for the purpose of destroying King Tiger and other heavily armored German tanks. This gun could penetrate 8.5 in (220 mm) of rolled homogeneous armor (RHA) at a range of 1,000 yd (914 m) against armor angled at 30 degrees. At a range of 100 yd (91 m), it could penetrate 13 in (330 mm) of RHA angled sloped at 30 degrees.
Near the end of World War II, more experimental versions of the 90mm gun were tested, including the T15E2 and the even higher velocity T18 and T19 main guns. The T19 was a T18 modified in an attempt to reduce barrel wear. Other versions included the T21, which was intended for wheeled vehicles, and the T22, which used the breech from the standard 105 mm M2 howitzer. The T21 and T22 were designed to use larger powder charges. None of these versions entered service.
In the post-WWII era, development of the T15 continued, now redesignated the T54, which included the ability to fire 90mm HVAP APCR-T projectiles at a muzzle velocity of 3,750 feet per second. The T54 served as the main gun main armament of the M26A1 Pershing, M47 and M48 Patton tanks used in the Korea War, as well as the M56 Scorpion anti-tank vehicle.
- Towed anti-aircraft gun. Approved for service in 1940.
- Fixed on M3 mount for Coast Artillery
Towed anti-aircraft gun. Production began in 1940. It featured the M8A1 spring rammer. Its rate of fire was 20 rounds per minute.
A complete redesign to make the gun dual role, functioning as an anti-tank gun as well as an anti-aircraft gun. The ammunition feed was upgraded and an automatic fuze setter/rammer, the M20, was added. This enabled the rate of fire to reach up to 24 rounds per minute. Elevation was improved with the gun able to depress to −10 degrees. To protect the crew, a large metal shield was added. The M2 was the standard weapon by May 13, 1943. From the march it could fire from its wheels in three minutes, and from a fully emplaced position in seven minutes. In 1944 the weapon was enhanced with the addition of proximity fused shells.
A tank/anti-tank version of the gun. It was used to equip the M36 tank destroyer and the M26 Pershing tank. It is also known as the 90 mm L/53.
- One AAA at NTC, Fort Irwin, CA post museum.
- One AAA at CFB Borden, Ontario, Canada
- One AAA at Sangudo Alberta 
- One AAA at Whycocomagh, Nova Scotia 
- One AAA at RCHA Museum, CFB Shilo, Manitoba, Canada
- One AAA at Shilo Manitoba, Canada (private collector)
- One AAA at Lembourg, Saskatchewan, Canada (private collector)
- One AAA at Fort Rodd Hill - Colwood, BC 
- One at Savannah, Georgia: National Guard Fairgrounds
- One at Arundel, Quebec, Canada: Legion Hall
- One AAA at Sault Ste Marie Ontario 
- One on barbette carriage at Shemya, Alaska. 
- One AAA M2 at U.S. Army Ordnance Museum in transit to US Army Air Defense Artillery Museum, Ft. Sill, Ok. 
- One AAA at Broadalbin, New York 
- One AAA at Roswell, New Mexico 
- One AAA at Greenville, South Carolina 
- One AAA at Anderson, South Carolina VFW post
- One AAA at Deming, NM Deming-Luna Museum
- One AAA at Utah Beach D-Day Museum, Sainte Marie du Mont, France. This gun belonged to the 116th AAA Gun Battalion and was lost in the Channel 6 June 1944. The gun was recovered by locals after the war.
- One AAA M1A3 (built 1954) at Raton, NM
- One AAA M1A1 at US Army Air Defense Artillery Museum, Ft. Sill, OK
- One AAA M2A2 at US Army Air Defense Artillery Museum, Ft. Sill, OK
- One AAA M1A1 at 31st ADA Brigade, Ft. Sill, OK
- One AAA M1A1 at Ft. Bliss Museum, Ft. Bliss, TX
- One AAA M1A1 at National Electronics Museum, MD
- Two Anti/Tank T-8 at National Armor & Cavalry Museum, Fort Benning, GA
- One M1A3 at National Guard Armory, Reidsville, GA
Weapons of comparable role, performance and era
- 8.8 cm Flak 18/36/37/41 : contemporary German anti-aircraft gun
- Cannone da 90/53 : contemporary Italian anti-aircraft gun
- QF 3.7-inch AA gun : contemporary British anti-aircraft gun, firing a heavier (28 pounds (13 kg)) shell
- 85 mm air defense gun M1939 (52-K) : contemporary Soviet anti-aircraft gun
- Green, Michael, Tiger Tanks At War, Zenith Press, ISBN 9780760331125, 076033112X (2008), pp. 118-122
- Armor-Piercing Ammunition for Gun, 90-mm, M3, Washington, D.C., U.S. Army: Office of the Chief of Ordnance (January 1945)
- Hunnicutt, R.P. Pershing: A History Of The Medium Tank T20 Series, Presidio Press, ISBN 0891416935, 9780891416937 (1999)
- TM 9-2300 standard artillery and fire control material. dated 1944
- TM 9-370
- TM 9-1370
- SNL D-28
|Wikimedia Commons has media related to 90 mm gun M1/M2.|
- United States War Department TM 9-374 Technical Manual 90-MM Gun M3 Mounted in Combat Vehicles. 11 September 1944
- M3 armor penetration table
- http://images.google.com/hosted/life/l?imgurl=2bf0edfbc39f5ef7&q=antiaircraft+source:life&usg=__lomzjGHj1yX6tAq-EY_2gyOR8_o=&prev=/images%3Fq%3Dantiaircraft%2Bsource:life%26hl%3Den AAA unit