3-inch Gun M7
The 3-inch Gun M7 (also known as the 76 mm Gun M7) is a high-velocity anti-tank cannon firing 76.2x585mmR shells. The gun was developed from the 3-inch M1918 anti-aircraft gun in American service. While it was adequate as an anti-tank gun, it was found to be too heavy for standard mounting on a tank. Thus, a new gun developed to be lighter and simpler was initiated and gave the 76 mm Gun M1 in 1942. While the two guns fire the same shells (but different casings), the 76 mm M1 would go on to become one of America's main high-velocity cannon mounted on tanks.
The 3-inch is the first high-velocity gun for the American tree for ground forces. The 3-inch gun gives Rank II a substantial increase in firepower against the standard Panzer IVs and T-34s. It has the same statistics as the 76 mm gun later seen on the M4 Shermans so the transition from a special cannon on heavy tanks and tank destroyers to a standard tank gun will be rather easy.
Guns of comparable performance
Available rounds for the gun:
- M79 Shot - Standard AP shell
- M42A1 Shell - Standard HE shell
- M62 Shell - APCBC round with explosive filler
- M93 Shot - APCR round
- M88 Shell - Smoke round
- M85 Shot - Target practice round
|Ammunition||Penetration in mm @ 90°|| Type of
Mass in kg
| Fuse delay
| Fuse sensitivity
| Explosive Mass in
| Normalization At 30°
History of creation and combat usage
The 3-inch gun started as an anti-aircraft gun called the 3-inch Gun M1918 and saw service in World War I. The gun was a modified coastal defense gun made to be able to aim at high elevations and on a mobile mount. It stayed as an anti-aircraft gun for the most part of the inter-war period, gradually upgraded with various features such as removable barrel liners, a shorter barrel, a semi-automatic breech and the such. It wasn't until September 1940 that the decision was made to adapt the 3-inch gun into an anti-tank role. The adaption was made, placing the gun onto a carriage, and was designated the 3-inch Gun M5 that first saw service in October 1943. Despite being more powerful than the standard infantry anti-tank gun 57 mm Gun M1 in US service, the 3-inch Gun M5 was criticized for being too heavy and bulky for effective usage. In comparison to other anti-tank guns at the time, such as the German Pak 40 and British 17-pounder, the anti-tank gun was inferior in all respect.
The gun was then mounted onto a motor vehicle, with the designation 3-inch Gun M7. This variant was first mounted on the American heavy tank prototype M6, but that project was cancelled part way into World War II. The gun was then to be mounted instead on a gun motor carriage that was to be a tank destroyer. This created the M10 tank destroyer. The gun performed superbly as an anti-tank weapon on the M10, taking out German tanks with ease, however its deployment in the tank destroyer units restricted its full efficiency as the tank destroyers were meant to be used in a defensive stance in case of a German armor breakthrough such as in their Blitzkrieg doctrine, thus keeping the tank destroyers and their large guns from being effective responders to front-line enemy tanks in fortified positions.
However, the 3-inch gun overall suffers from its heavy weight and largeness. Dedicated mounts had to be made to use the gun, and its adaption onto the standard issue M4 Shermans in American service was impossible. Thus, development started for a lighter variant of the caliber. The finished product was the 76 mm Gun M1, developed in 1942 that is able to be mounted onto the Sherman much more easily. The 76 mm gun would succeed the 3-inch gun as the general high-velocity cannon in American service, but the 3-inch would still see service in the M10 carriages until the end of World War II.