20 mm Polsten
| Polsten | |
|---|---|
A Canadian towed anti-aircraft mounting featuring three Polsten cannons. | |
| Type | Autocannon |
| Place of origin | Poland United Kingdom |
| Service history | |
| In service | 1944−1950s |
| Used by | See § Users |
| Wars | |
| Production history | |
| Designed | 1939−1941? |
| Manufacturer | John Inglis |
| Unit cost | £60−£70 |
| Specifications | |
| Mass | 57 kg (126 lb) |
| Length | 2.1 m (6 ft 11 in) |
| Barrel length | 1.45 m (4 ft 9 in) (barrel) |
| Calibre | 20 mm (0.78 in) |
| Action | API blowback |
| Rate of fire | 450 rpm |
| Muzzle velocity | 830 m/s (2,700 ft/s) |
| Effective firing range | 1,000 m (3,281 ft) |
| Maximum firing range | 2,000 m (6,562 ft) |
| Feed system | 60 round drum magazine or 30 round box magazine |
The Polsten was a Polish development of the 20 mm Oerlikon gun. The Polsten was designed to be simpler and much cheaper to build than the Oerlikon, without reducing effectiveness. It was widely produced and used by the British Army and many allied and commonwealth forces, including production in Canada and Australia.