The immediate post-war period saw the final fielding of heavy tanks, including the US M103 heavy tank, the British FV214 Conqueror, and the French ARL 44 (in very limited numbers for the ARL 44), all in response to the Soviet heavy tanks of the period. The largest tank guns were approaching maximum calibre whose shell could still be handled by the crew, even using awkward two-part ammunition (separate projectile and propellant case, similar to battleship guns), which greatly slowed their rate of fire. Thanks to improved shell designs and fire control technology improving accuracy, postwar medium tanks were catching up to heavy tanks in firepower.