Russian
2.5"/38 (6.33 cm) Pattern 1916
63.3 mm/38 (2.5") Pattern 1916
Updated 21 May 2006
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.
WNRussian_25-38_m1916_Rostislav_pic.jpg

Russian battleship Rostislav in 1916
The 2.5"/38 (6.33 cm) gun is on top of the turret
Photograph from "Warships of the Russian Fleet:  1914-1917"
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Gun Characteristics
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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
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Ammunition
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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
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Range
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Elevation With 8.91 lbs. (4.04 kg) Shrapnel Shell
Range @ 20 degrees 7,440 yards (6,804 m)
AA Range @ 80 degrees 19,700 feet (6,000 m)
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Mount / Turret Data
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Designation Single Pedestal
Weight 2,866 lbs. (1,300 kg)
Elevation -5 / +75 degrees
Rate of Elevation Manual operation, only
Train 360 degrees
Rate of Train Manual operation, only
Gun Recoil Elevation @ 0 degrees:  29.5 in (75 cm)
Elevation @ 75 degrees:  35.4 in (90 cm)
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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
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Special help from Vladimir Yakubov