76 mm gun M1

The 76 mm gun M1 was an American World War II-era tank gun, which replaced the 75 mm gun on late Medium tank M4s, and was used for all 76 mm Gun Motor Carriage M18 tank destroyers. The previous 75 mm M3 L/40 gun on the early M4 Sherman variants was designed more as an infantry support weapon. The performance of this gun against armor was considered insufficient and led to the design of a higher velocity weapon.

Design and development
It was a new gun with a breech similar to that of the 75 mm M3 Gun. It fired the same shell as the 3 in gun of the 3in Gun Motor Carriage M10 tank destroyer, but from a different case. The 76 mm was developed as a lighter gun than the "3 inch". The gun received a muzzle brake and faster rifle twist during production.

While the 76 mm had less High Explosive (HE) and smoke performance than the 75 mm, the higher-velocity 76 mm gave better anti-tank performance, with firepower similar to many of the armored fighting vehicles it encountered, particularly the Panzer IV and StuG vehicles.

The M1 was tested on an M4 Sherman tank, it was then found that the long barrel caused balance problems. The barrel was shortened and a counterweight added to the breech to compensate giving the M1A1. The reduction in length - by about 15 inches - reduced performance but the 76 mm was still superior to the 75 mm gun.

When the counterweight was found to be insufficient, the turret design of the T23 tank was used on the M4 chassis to carry the 76mm gun.

Wholesale introduction of the 76 mm gun was opposed due to its inferior HE round - approx 0.9 lb of explosive to the 1.5 lb in the 75 mm round - and the muzzle blast which could create large dust clouds in dry conditions.

The UK was not interested in the 76 mm gun Sherman as they had their own guns under development - although of intermediate length between the M1 and M1A1 76 mm, their Ordnance QF 17 pounder (76.2 mm) antitank gun used about 5.5 lb more propellant. Armed with this gun the M4 was known as the Sherman Firefly.

Variants

 * M1 -57 calibre long gun
 * M1A1 - 52 calibre long version of gun with breech counterweight.
 * M1A1C - fitted with muzzle brake
 * M1A2 - fitted with muzzle brake

Usage
With British Commonwealth designations in brackets


 * 76 mm Gun Motor Carriage M18 (Hellcat)
 * Medium Tank M4A1(76)W (Sherman IIA)
 * Medium Tank M4A1(76)W HVSS (Sherman IIAY)
 * Medium Tank M4A2(76)W (Sherman IIIA)
 * Medium Tank M4A2(76)W HVSS (Sherman IIIAY)
 * Medium Tank M4A3(76)W(Sherman IVA)
 * Medium Tank M4A3(76)W HVSS

76 mm gunned Shermans supplied to the British were only used in Italy or by the Polish 1st Armoured Division in North-West Europe. The British supported their 75 mm gunned Shermans with QF 17 pdr (76mm) equipped "Fireflies"

Towed variant
From 1943, at the instigation of the head of the Armored Force General Jacob Devers, US Ordnance worked on a towed anti-tank gun based on the barrel of the M1, known as "76 mm gun T2 on carriage T3". Later interest in the project declined and in 1945 the program was officially canceled.