US and UK forces also deployed vehicles designed for a close support role, but these were conventional tanks whose only significant modification was the replacement of the main gun with a howitzer. Two versions of the American Sherman tank were armed with the M4 105 mm howitzer, the M4(105) and the M4A3(105); these were designated assault guns in US usage of the term. The M8 Scott, based on the chassis of the M5 Stuart light tank, was also an assault cannon and carried a 75 mm short howitzer. The Churchill, Centaur and Cromwell tanks were all produced in versions armed with 95 mm howitzers: the Churchill Mark V and Mark VIII, the Centaur Mark IV and the Cromwell Mark VI. Earlier British tanks, such as the Crusader cruiser tank and the Matilda II Infantry tank were produced in versions armed with the 3-inch howitzer; the first versions of the Churchill tank also had this gun in a hull mounting. American tank destroyer units were often used in the assault gun role for infantry support.