| BL 5.5 inch medium gun Mk 3 | |
|---|---|
 A 5.5 Inch Gun Crew on the Italian Front, 10 January 1944. | |
| Type | Medium gun |
| Place of origin | United Kingdom |
| Service history | |
| In service | 1941–1980 (UK) |
| Used by | See users |
| Wars | World War II Korean War Portuguese Colonial War Rhodesian Bush War South African Border War Iran–Iraq War |
| Production history | |
| Produced | 1941-1945 |
| No. built | 5,000 |
| Specifications | |
| Mass | 13,647 lbs (6,190 kg) |
| Length | 24 ft 7 in (7.5 m)[1] |
| Barrel length | 13 ft 9 in (4.19 m) L/30 |
| Width | 8 ft 4 in (2.54 m) |
| Height | 8 ft 6 in (2.6 m)[1] |
| Crew | 10 |
| Shell | Separate loading bagged charge and projectile[1] |
| Calibre | 5.5 inch (140 mm) |
| Breech | Welin breech and Asbury mechanism |
| Recoil | Hydro-pneumatic |
| Carriage | Split trail |
| Elevation | -5° to 45° |
| Traverse | 30° left and right |
| Rate of fire | 2 rpm |
| Muzzle velocity | 100lb shell (45 kg): 1,675 ft/s (511 m/s) 82lb shell (37 kg): 1,950 ft/s (590 m/s) |
| Maximum firing range | 100lb shell: 16,200 yards (14,800 m) 82lb shell: 18,100 yards (16,600 m) |
| Sights | Probert pattern reciprocating and calibrating |
The BL 5.5-inch gun was a British artillery gun introduced during the Second World War to equip medium batteries.