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 medium-velocity 75 mm M3 L/40 gun, which
armed the standard M4 Sherman, was designed as a dual purpose weapon.
Although quite capable of dealing with the initially 30 mm to 50 mm thick
frontal armor of German Panzer IV tanks and StuG III assault guns, the
subsequent uparmoring of these AFVs to 80 mm and upgunning to the KwK 40/StuK
40 diminished the ability of the Sherman to engage at long distances. Due to the
appearance of the Panther and Tiger tanks on the field, a higher velocity
weapon was demanded. The new 76mm gun represented a much
needed increase in anti-tank performance, allowing the Sherman to
engage the most common German armored vehicles like the Panzer IV and Stug
III. 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-inch M7 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
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. Using
the M62 APC round, the 76mm gun penetrated 109 mm of armor at 1,000 m,
with a muzzle velocity of 792 m/s. The HVAP round was able to penetrate 178 mm
at 1,000 m, with a muzzle velocity of 1,036 m/s.
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 this did not however reduce performance; penetration figures
remained the same. 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—approximately 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. Later production guns were given a muzzle
brake to deflect the blast sideways. The UK was not interested in the 76 mm
gun Sherman as they had their own guns and tanks under development—although of
intermediate length between the M1 and M1A1 76 mm, their Ordnance QF 17 pounder
anti-tank gun used about 5.5 lb more propellant. Developed as an expediency
M4 Shermans converted to use the 17pdr were known as the Sherman Firefly.
The anti tank performance of the 76mm was inferior to the British 17 pounder,
and even more so if the latter was using discarding sabot rounds, though with
that ammunition the 17pdr was less accurate than the 76mm.
Variants M1: 57 caliber long gun
M1A1: 52 caliber long version of gun with breech counterweight.
M1A1C: fitted with muzzle brake M1A2: fitted with muzzle brake
Usage With British Commonwealth designations
in parentheses: 76 mm Gun Motor Carriage M18
Medium Tank M4A1(76)W Medium Tank M4A1(76)W HVSS
Medium Tank M4A2(76)W Medium Tank M4A2(76)W HVSS
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 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. Performance
Penetration comparison See also
List of U.S. Army weapons by supply catalog designation
= Weapons of comparable role, performance and era=
British Ordnance QF 17 pounder German 7.5 cm KwK 40
German 7.5 cm KwK 42 Notes
Further reading TM 9-308
SNL C-46 SNL C-58
SNL C-64 External links
USA 75 and 76mm guns http:www.wwiivehicles.comguns/76-mm.asp