In 1932 the "Bolshevik" factory was tasked to create a new 100 mm (3.9") gun for use in submarines and small combatants. The first gun was made in 1935 and trials lasted until 1936, when it was accepted in to service. In 1937 the gun was modified and was redesignated B-24-IIc.
In 1938 the design was lengthened to 56 calibers and accepted into service in 1939. This new design used a gun shield and was for small combatants.
By 1941 there were 76 guns of both types in service. During the war only five B-24 guns were made but in 1946-50 a further 63 were made for use on submarines.
The B-24 gun was made from A tube, fastened with a casing which was assembled while the gun was hot. The B-24BM gun was made from loose-liner, casing and breech. The breech mechanism was semi-automatic, pneumatic, horizontal sliding breech-block in the guns made prior to 1942 and a spring-driven, semi-automatic breech in all later versions. All of the mechanisms in both guns were identical except for the gun sight and the shield.
| Designation | 100 mm/51 (3.9") B-24 Pattern 1936
100 mm/56 (3.9") B-24BM Pattern 1939 |
|---|---|
| Ship Class Used On | B-24 PL
L class (series II, XI, XIII, XIII-38), S class (series IX, IXbis, XVI), K class (series XIV) D class (series I) (rearmed), MZ class (Project 99) (cancelled) submarines B-24BM
|
| Date Of Design | B-24: 1935
B-24BM: 1938 |
| Date In Service | B-24: 1936
B-24BM: 1939 |
| Gun Weight | B-24: 2.387 tons (2.425 mt)
B-24BM: 2.671 tons (2.713 mt) |
| Gun Length oa | B-24: 200.79 in (5.100 m)
B-24BM: 228.15 in (5.795 m) |
| Bore Length | B-24: 190.95 in (5.100 m)
B-24BM: 210.63 in (5.350 m) |
| Rifling Length | B-24: 162.21 in (4.120 m)
B-24BM: 182.09 in (4.625 m) |
| Grooves | 40 |
| Lands | N/A |
| Twist | N/A |
| Chamber Volume | 486.8 in3 (7.98 dm3) |
| Rate Of Fire | 12 rounds per minute |
| Type | Fixed |
|---|---|
| Weight of Complete Round | about 61.7 lbs. (28 kg) |
| Projectile Types and Weights | AA grenade: 34.39 lbs. (15.6 kg)
AA (ZS-56): 34.39 lbs. (15.6 kg) AA (ZS-56P): 35.05 lbs. (15.9 kg) HE mod 1928 (F-56): 34.83 lbs. (15.8 kg) Diving: 33.07 lbs. (15.0 kg) Star Shell (SB-56): 35.27 lbs. (16.0 kg) ECM (anti radar) (PB-56): N/A |
| Bursting Charge | AA grenade: 2.67 lbs. (1.21 kg)
AA (ZS-56): 2.71 lbs. (1.23 kg) AA (ZS-56P): 1.74 lbs. (0.79 kg) HE mod 1928 (F-56): 2.76 lbs. (1.25 kg) Diving: 6.28 lbs. (2.85 kg) Star Shell (SB-56): 0.03 lbs. (0.015 kg) ECM (anti radar) (PB-56): reflective material DOS-15 |
| Projectile Length | AA grenade: 5.3 calibers
AA (ZS-56): 5.13 calibers AA (ZS-56P): 5.0 calibers HE mod 1928: 5.2 calibers Diving: 5.04 calibers Star Shell (SB-56): 5.2 calibers |
| Propellant Charge | 13.2 lbs. (6 kg) |
| Muzzle Velocity | B-24
AA grenade: 2,861 fps (872 mps) HE mod 1928: 2,638 fps (804 mps) Diving: 820 fps (250 mps) B-24BM
|
| Working Pressure | 19.7 tons/in2 (3,100 kg/cm2) |
| Approximate Barrel Life | 800 rounds |
| Ammunition stowage per gun | K-class, S-class, submarines: 200 rounds
L-class (series II, XI) submarines: 122 rounds L-class (series XIII, XIII-38) submarines: 150 rounds Uragan class: 150 rounds |
| Elevation | Distance |
|---|---|
| Maximum Range (B-24BM) | 24,323 yards (22,241 m) |
| Maximum Range (B-24) | 24,402 yards (22,314 m) |
| Elevation | Distance |
|---|---|
| Maximum Timer Range (B-24BM) | 10,821 yards (9,895 m) |
| Maximum Timer Range (B-24) | 10,551 yards (9,648 m) |
| Designation | Single Mounts: B-24, B-24-IIc, B-24BM, B-24PL |
|---|---|
| Weight | B-24BM: 7.284 tons (7.4 mt)
B-24-IIc: 5.217 tons (5.34 mt) B-24PL: 5.414 tons (5.5 mt) |
| Elevation | -5 / +45 degrees |
| Rate of Elevation | 5 degrees |
| Train | 360 degrees |
| Rate of Train | 5 degrees |
| Gun Recoil | @ 0 degrees: 24.43 in (595 mm)
@ 85 degrees: 26.77 in (680 mm) |
"Sovetskie Boevye Korabli 1941-45: IV Vooruzhnie" (Soviet Warships 1941-45: Volume IV Armament) by A.V. Platonov
"Entsiklopedia Otechestvennoi Artillerii" (Encyclopedia of Fatherland (Russian) Artillery) by A.V. Shirokorad
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"Flot vo Slavu Rossii" (Fleet in Honor of Russia) CD
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Special help from Vladimir Yakubov and Larry Sawh