In 1940 the Canadian Government decided to build a Cruiser tank for the Canadian army, using parts from the US M3 Lee. The first pilot tank was ready by November 1941, using the entire M3 lower hull, but with new cast upper hull and turret. The first 50 tanks were designated the Ram MkI and mounted a 2 Pounder gun. However the main production version would be the MkII with a powerful 6 Pounder anti-tank gun. Unfortunately the 6 Pounder was not ready until April 1942, and by this time the American M4 Sherman was entering mass production. The Ram was no longer needed as a combat tank, but was produced as a training tank. The Ram MkII weighed 29 tons and had armour up to 87mm thick. Powered by a 400bhp Continental R-975 radial, the Ram had a maximum road speed of 40 km/h. The 6 Pounder gun could penetrate 90mm of armour at 1,000 meters, using APCBC ammunition. The early Ram MkII's had side doors in the hull sides and a machine gun sub-turret, which were eliminated in later versions. Some 2,032 Ram tank were built and were used for training both in Canada and in the UK. A few Ram tanks were used in action as Armoured Observation Post (AOP) and Gun Position Officer (GPO) tanks with the Royal Canadian Artillery regiments. Many Ram's had their turrets removed and were converted to Ram Kangaroo heavy APC's, or gun tractors. These being used in N. W. Europe 1944-45. In 1945 Ram tanks were used to equip two Dutch armoured battalions, remaining in service until replaced with Centurion tanks in 1952. The Ram tank was used as the basis of the highly successful Sexton 25 Pdr Self Propelled Gun.