M3 GMC

Infobox Weapon
name=75 mm Gun Motor Carriage M3


caption=
origin=USA
type=Tank destroyer / self-propelled artillery
is_vehicle=yes
length=6.24 m (20.46 ft)
width=2.16 m (7.08 ft)
height=2.44 m (8.02 ft)
weight=9.07 tonnes (20,000 lb)
suspension=Semi-Elliptic Volute Spring
speed=70 km/h (45 mi/h)
vehicle_range=320 km (200 mi)
primary_armament=75 mm Gun M1897A4
59 rounds
secondary_armament=None
armour= 6-16mm (0.25-0.63in)
engine=White 160AX
engine_power=142.5 hp (105 kW)
pw_ratio=15.71 hp/tonne
crew=5 (Commander, (3x) gun crew, driver)

The 75 mm Gun Motor Carriage M3 was a United States TD (Tank Destroyer) and self-propelled artillery piece of the Second World War.

Development

The German victory over France in 1940 using armored divisions profoundly impressed the United States Army. Realizing that defense against tanks was essential, an urgent requirement was issued for the development of tank destroyers for the U.S. Army. In June 1941, an M3 Halftrack was mated with an M1897A4 75 mm gun, which was an American version of the famous "French 75" of World War I fame. This experimental vehicle was known as the T12, and proved to work remarkably well given the speed with which it was developed. Standardized in October 1941 as the 75 mm GMC M3, over 2,200 75 mm GMC M3's were produced until April 1943. However, a large number of them were converted back to standard halftracks before issue to troop units, resulting in 842 seeing field service. [Zaloga, Stephen J., M3 Infantry Halftrack, page 35. Oxford: Osprey Publications, 1994, ISBN 1-85532-467-9.] The GMC M3A1 was a variant that used a different gun mount. The 75 mm GMC M3 was reclassified first as limited standard and then as obsolete in 1944.

American Use

Confronted with an impending war with Japan, 75 GMC M3's and T12's, termed SPM (Self-Propelled Mount) halftracks, were shipped to the Philippine Islands in September 1941 to form the (2nd) Provisional SPM Brigade. These vehicles saw action during the Japanese invasion of the Philippines, and some were later captured by the Japanese and used against U.S. forces in 1944. [Zaloga, Stephen J., M3 Infantry Halftrack, page 33. Oxford: Osprey Publications, 1994, ISBN 1-85532-467-9.]

The GMC M3 was the most widely-deployed TD in U.S. tank destroyer battalions during the campaign in Tunisia in late 1942 and early 1943, and was prominent during the battles of Sidi Bou Zid, Kasserine Pass, and El Guettar. Although many GMC M3's were lost in these battles, the U.S. Army concluded that improper employment had caused some of these losses. The GMC M3 was again used in the tank destroyer role in the Sicilian Campaign in July 1943. Subsequently, the GMC M3 was phased out of tank destroyer battalions and replaced by the GMC M10, a turreted TD mounting a 3-inch gun. Although then considered obsolete for use against German tanks, the GMC M3 was easily powerful enough to destroy the light tanks deployed by the Japanese, and so the GMC M3 continued to be used in the Pacific Theater, primarily with regimental weapons companies of the U.S. Marine Corps, seeing action on Saipan, Peleliu, and Okinawa, among other island battles. Because tanks were not frequently deployed by the Japanese, the GMC M3 was often used as a self-propelled artillery piece or for direct fire support against Japanese fortifications. In 1945, the GMC M3 was replaced in Marine Corps use by the 105 mm HMC M7 self-propelled artillery piece. [Rottman, Gordon L., U. S. Marine Corps Order of Battle, page 523. Westport: Greenwood Press, 2002, ISBN 0-313-31906-5.]

Allied Use

Around 170 GMC M3's were provided to the British Army in early 1943. The British deployed them in the headquarters troops of armoured car and tank units as self-propelled artillery pieces. These GMC M3's ("75 mm SP, Autocar" in British nomenclature) were employed in Tunisia and Italy. [Chamberlain, Peter, and Ellis, Chris, British and American Tanks of World War Two, page 189. London: Cassell & Co., 2000, ISBN 0-304-35529-1.] The 75 mm GMC M3 was also used by the French Army on a limited basis during 1944 - 1945.

Description

The 75 mm GMC M3 was an M3 Halftrack with an M1897A4 75 mm gun mounted in the rear of the halftrack. The gun had an indirect fire range of 9,200 yards (8,400 meters), [Rottman, Gordon L., U. S. Marine Corps Order of Battle, page 523. Westport: Greenwood Press, 2002, ISBN 0-313-31906-5.] and fired the AP M72 (Armor Piercing) shell that could penetrate 3.2 inches of armour at 500 yards, the APC M61 (Armor Piercing Capped) shell that could penetrate 2.8 inches of armour at 500 yards, and the HE M48 (High Explosive) shell for use against infantry and other non-armored targets. 59 rounds of 75-mm ammunition were carried aboard. [Hogg, Ian V. (introduction), The American Arsenal, page 44. Mechanicsburg: Stackpole Books, 2001. This is a reprint of the U.S. War Department "Ordnance Standard Catalog". Other reference data for the GMC M3 is provided as well.]

The crew were equipped with a rifle and four carbines for self defense.

External links

* [http://www.ocshistory.org/army_museum/TD?index.html Tank Destroyer OCS]

Citations