#37mm

The ZSU-37 (not to be confused with the ZSU-37-2) is a SPAAG built by the USSR that was based on the chassis of the SU-76M in late 1943–44 but never saw service due to its late introduction. The 37-millimeter gun can fire clips of either high-penetrating AP-T/HVAP-T anti-armor belts, or a very powerful HEFI-T* anti-aircraft belt. With this vehicle, the main issue is not downing planes in one shot but hitting planes in the first place.