BK 3.7 Specifications
• Type: single-barrel automatic cannon
• Caliber: 37 mm (1.46 in)
• Cartridge: 37 mm x 263
• Operation: Short Recoil
• Length: 3.63 m (11 ft 11 in)
• Weight: 295 kg (650 lb)
• Rate of fire: 160 rpm
• Muzzle velocity: 1,170 to 780 m/s (3,836 to 2,557 ft/s)
• Projectile weight: APCR 380 g, HE 640 g, AT 685 g
The remaining German guns were all adaptations of ground guns. The first was the 37 mm BK 3,7, a modified version of the FlaK 18 AA gun firing the same 37x263B ammunition. This meant that it was bulky, heavy and slow-firing by comparison with the NS-37, for example. It also remained clip-fed, with a maximum capacity of just 12 rounds. It mainly fired Hartkernmunition ammo, capable of penetrating up to 140 mm / 100 m / 90 degrees although this was halved at a striking angle of 60 degrees.
NS 37 Specifications
• Type: single-barrel automatic cannon
• Caliber: 37 mm (1.46 in)
• Operation: short recoil
• Length: 2455mm (N-37D)
• Weight (complete): 103 kg (227 lb)
• Rate of fire: 400 rpm
• Muzzle velocity 900 m/s (HE, HEI-T), 880 m/s (AP-T)
• Projectile weight: 735 g (26 oz)
The NS-37, unusually for the USSR, used a short-recoil mechanism and was belt-fed. It was a particularly slim weapon, with a compact mechanism, suitable for fitting between the banks of a liquid-cooled vee-engine to fire through the hollow propeller hub. The powerful 37x195 ammunition is quoted as penetrating 48mm / 500m / 90 degrees, enough to pose a threat to the side or rear armor of virtually any tank.
Um who's right?