The 3-inch gun M5 was an anti-tank gun developed in the United States during World War II. The gun combined a barrel of the anti-aircraft gun T9 and elements of the 105 mm howitzer M2. The M5 was issued exclusively to the US Army tank destroyer battalions starting in 1943. It saw combat in the Italian Campaign and on the Western Front in Northwest Europe.
While the M5 outperformed earlier anti-tank guns in the US service, its effective employment was hindered by its heavy weight and ammunition-related issues. Losses suffered by towed TD battalions in the Battle of the Bulge and the existence of more mobile, better protected alternatives in the form of self-propelled tank destroyers led to gradual removal of the M5 from front line service in 1945.
Development and production history
In 1940, the US Army just started to receive its first anti-tank gun, the 37 mm gun M3. While it fit the request of the Infantry for a light, easy to manhandle anti-tank weapon, the Field Artillery and Ordnance Department foresaw a need for a more powerful gun. This led to a number of expedient designs, such as variations of the 75 mm gun M1897.
Late in 1940, the Ordnance Department started another project – an anti-tank gun based on the 3 inch anti-aircraft gun T9. The barrel of the T9 was combined with breech, recoil system and carriage, from the 105 mm howitzer M2. The pilot of the weapon, named 3 inch gun T10, was ready by September 1941. Although the subsequent testing revealed minor problems, it was clear that the gun, eventually standardized as M5 on carriage M1, presented major performance improvement over existing designs.
Production began in December 1942. In November 1943, a slightly modified carriage was standardized as M6. In this carriage, a flat shield borrowed from the 105 mm howitzer was replaced by a new sloped one. In January 1944, AGF requested an upgrade of those guns built with the early carriage M1 to the carriage M6; consequently most of the guns that reached the frontline had the M6 carriage.
Description
The barrel was adapted from the 3-inch gun T9; it had rifling with a uniform right-hand twist, with 28 grooves and one turn in 25 inches. Barrel length was 13.16 feet. It was combined with breech, recoil system and carriage from the 105 mm Howitzer M2. The breech was of horizontal sliding type, manual; the recoil system hydro-pneumatic. The carriage was of split trail type, equipped with a single equilibrator spring beneath the breech and wheels with pneumatic tires.
Organization
Despite the performance advantages, it turned out that no branch of the US Army wanted the new gun. The Infantry considered it too large and heavy. The other possible user, the Tank Destroyer Center, preferred more mobile self-propelled weapons. Finally, pressure from the head of Army Ground Forces, Gen. Lesley McNair, resulted in the gun being adopted by the TD Center. McNair's opinion was apparently influenced by the experience of the North African Campaign, where self-propelled guns were found to be hard to conceal.
On 31 March 1943, AGF ordered 15 self-propelled tank destroyer battalions to convert to a towed form; eventually, AGF decided that half of the TD battalions should be towed. A towed TD battalion possessed 36 pieces, in three companies of 12. M3 Halftracks were issued as prime movers. The organization from 1 September 1944 authorized M39 Armored Utility Vehicle instead, but these only reached the frontline in spring 1945.
Those towed tank destroyer battalions were attached to US Army divisions to improve their anti-tank capabilities. Most often, a complete battalion was attached to an infantry division. In some cases, towed TD battalions were attached to armored or airborne divisions; sometimes, companies of the same battalion were given to different divisions; and sometimes a single division had several TD battalions – including a mix between towed and self-propelled – at once.
Combat service
In October 1943, the first towed battalion – the 805th – arrived in Italy. Subsequently, the M5 saw combat in the Italian Campaign and in the Northwest Europe. One of the most notable engagements came during the German counterattack on Mortain in August 1944. The 823rd Tank Destroyer Battalion, attached to the 30th Infantry Division, played a key role in the successful defence of Saint Barthelemy, destroying fourteen tanks and a number of other vehicles, though at the price of losing eleven of its guns.