ST-10 (СТ-10) and a panoramic sight. For crew communication a TPU-4-BisF intercom was fitted, and for inter-vehicle communication there was a single radio. The first-series SU-152 was equipped with the 9R, then 10R and finally the 10RK-26 radio set. These radios were better than Soviet equipment at the start of the war, but inferior to German equipment. The crew was equipped with two PPSh submachine guns and 25 F1 grenades for short-range self-defence. Combat history Although not designed for the role, the SU-152 proved to be a cheap and effective heavy tank killer, second only to the SU-100 as a Soviet antitank vehicle, as well as successful at its original role against infantry and fortifications, serving a similar role to the SU-100Y. The SU-152 was produced in large numbers throughout 1943, with the first SU-152s being issued to new heavy mechanized gun regiments raised in May 1943. The first regiment arrived at Kursk with only 12 guns, and was brought up to its full strength of 21 guns during the fighting. Disadvantages of the vehicle included a low rate of fire due to the heavy ammunition, low ammunition storage (only 20 rounds), and a cramped and un-ergonomic crew compartment. Its armor protection was only adequate; the 65 mm of 30-degree sloped frontal armor still left it vulnerable frontally to the 88 mm KwK 36/43 guns of the Tiger and Ferdinand/Elefant at long range and the 7.5 cm KwK 40 high-velocity gun of the Panzer IV and StuG III/IV at medium and short ranges (and from any range from the flanks or rear). The 152 mm gun, while having a maximum range far superior to the 88 mm, was still essentially a heavy howitzer with a shorter accurate range than the 88 mm and 7.5 cm guns while being vulnerable to return fire at the same distance. This made it most effective for use against entrenched enemies, where the German heavy tanks' advantages could be nullified and the SU-152s could utilise their one-shot kill potential. Since it was intended as a self-propelled artillery piece rather than a true tank destroyer, the SU-152 was generally issued with standard HE rounds rather than armor-piercing projectiles. The 152mm HE round produced a massive blast that did not rely on velocity for its effectiveness, making it effective against any German tank, including the Tiger and Elefant (although still less effective than penetrating projectiles). It was