The second version of the “beast killer,” the ISU-152 took the exact same idea behind the SU-152 and improved on it slightly. The taller, more rectangular casemate could hold more ammunition and provided more room for the crew to work. The extra room allowed for several experimental super-heavy tank destroyers to be built on the platform, such as the ISU-152-1, which was armed with the 8-metre-long 152,4mm BL-8 cannon. Such a vehicle was meant to be a dedicated tank destroyer, for use against the heaviest of German vehicles. However, the BL-8 was longer than optimal, so the shorter BL-10 actually had a higher muzzle velocity, and was put on the ISU-152-2. Neither of these vehicles were seen as particularly practical, possibly because the Panzer 8 “Maus” never entered combat. Unlike its predecessor, the ISU-152 was still seen as a useful self-propelled artillery device well after the war, and a modernised version, ISU-152K, entered production in 1956. This version had a different engine deck, improved armour, and many internal components, including the engine, taken from the T-54 medium tank. A second modernised version, ISU-152M, entered production in 1959, though it appears to be identical to the original on the outside, with only internal differences setting it apart.