The British nomenclature for 76mm gun Shermans involved adding an "A" to the designation, so M4A1(76)W became Sherman IIA.
Wet ammunition stowage was incorporated into the M4A1(76)W, hence the "W" suffix in the designation. This involved storing the ammunition in double-walled boxes. The space between the walls of the boxes were filled with water; ethylene glycol to prevent freezing; and Ammudamp, a rust inhibitor. When these boxes were penetrated, the water would snuff out the resulting ammunition fire. Wet ammunition stowage, and the stowage of most of the ammunition under the turret rather than in the sponsons, drastically reduced the Sherman's propencity to burn; the "W" tanks were no longer "Ronsons." In 76mm gun tanks there was a 6-round ready rack in the turret surrounded by 2.1 gallons (7.9L) of water and a box on either side of the drive shaft, one holding 30 rounds and the other 35, with a total of 34.5 gallons (131L) of water. The welded applique armor was eliminated in wet stowage tanks, as well as most of the turret basket to enable use of the floor ammunition boxes. A partial floor was retained which was suspended from the turret ring.
Seventy-six-millimeter gun tanks used a new turret modified from the medium tank T23. The T23 was never standardized, but that test series went on to produce improvements that were incorporated into other tanks (like the T23's turret), and ultimately culminated in the M26 Pershing. The turret of the first M4A1(76)Ws were fitted with a split hatch for the loader, which was replaced with the small oval hatch about one-third of the way through the production run.
The 76mm guns themselves differ in the following ways: the outside recoil surface of the M1A1 was lengthened by one foot over the M1, thereby allowing the trunnions to be moved forward and providing better gun balance; the M1A1C had the end of the barrel threaded for a muzzle brake; the rifling of the M1A2 was one turn in 32 calibers versus one turn in forty for the other weapons. All M1A2s were equipped with muzzle brakes.
