This was an AA weapon designed by OSZ early in World War I. By the end of November 1916 twenty guns had been built and another twenty started. Most of the first batch appear to have been sent to arm the Black Sea Fleet. Widely used on battleships during World War I but removed following the war. By 1923 there were 23 guns in storage at OSZ.
Overall the gun was unsuccessful as it was only semi-automatic and its shells had a small lethal radius. The Russians considered the 3" (7.62 cm) Lender gun to be a more effective AA weapon.
Breech was vertical sliding-breech block type.
| Designation | 2.5"/38 (6.33 cm) Pattern 1916 63.3 mm/38 (2.5") Pattern 1916 |
|---|---|
| Ship Class Used On | Izmail class BCs, Gangut class BBs, Evstafii class BBs, Rostislav BB, Tri Svyatitelya BB, Izyaslav class DDs and some Orfei class DDs |
| Date Of Design | 1914-15 |
| Date In Service | 1916 |
| Gun Weight | N/A |
| Gun Length oa | 94.69 in (2.405 m) |
| Bore Length | 89.21 in (2.266 m) |
| Rifling Length | N/A |
| Grooves | N/A |
| Lands | N/A |
| Twist | N/A |
| Chamber Volume | N/A |
| Rate Of Fire | N/A |
| Type | Fixed |
|---|---|
| Weight of Complete Round | N/A |
| Projectile Types and Weights | Shrapnel: 8.91 lbs. (4.04 kg) Distance Grenade: 8.22 lbs. (3.73 kg) |
| Bursting Charge | Distance Grenade: 1.76 lbs. (0.8 kg) |
| Projectile Length | Shrapnel: 4 calibers Distance Grenade: 4 calibers |
| Propellant Container Type and Weight | Cartridge: N/A |
| Propellant Charge | 1.77 lbs. (0.82 kg) |
| Muzzle Velocity | 2,251 fps (686 mps) |
| Working Pressure | N/A |
| Approximate Barrel Life | N/A |
| Ammunition stowage per gun | 200 rounds |
| Elevation | Distance |
|---|---|
| 20 degrees | 7,440 yards (6,804 m) |
| AA Range @ 80 degrees | 19,700 feet (6,000 m) |
Data from:
- Warship International No. 3, 1998, Letter to the Editor by Steve McLaughlin and Christopher C. Wright
- "Entsiklopedia Otechestvennoi Artillerii" (Encyclopedia of Fatherland [Russian] Artillery) by A.V. Shirokorad
Special help from Vladimir Yakubov