The SU-152 heavy self-propelled gun, Called the Big Game Hunter or Zookeeper, was an effective antidote to the German Tiger and Panthers tanks. This was the 152mm ML-20 gun-howitzer mounted on a KV-1s hull. 704 were produced, but only a single regiment (6 batteries of 2 SU-152) was available in time for the battle of Kursk. The 152mm gun-howitzer fired a massive Armour Piercing High Explosive (APHE) shell that would smash any tank in existence at the time. The weapon was relatively low velocity, which meant that at long range the shell would be dropping onto the enemy tank (because of the curved trajectory of the round) and ploughing through the thinner armour on its deck. At closer range the kinetic and explosive energy of the shell could rip the turret clean off a tank. But the downside of this power was a low rate of fire and limited ammunition capacity (only 20 rounds were carried in each SU-152).