Russian
100 mm/70 (3.9") CM-5
Updated 18 November 2006
This gun was designed specifically for the Chapaev class (Pr.68) cruisers.  Manufactured between 1948 and 1955 with a total of 150 weapons being built for the five Chapaev class and twenty Sverdlov class (Pr.68bis) cruisers.

These guns were controlled by the "Zenit-68bis A" Fire Control System which was used to control both these guns and the smaller AA guns.  This system included a "Yakor'" radar and a SPN-500 radar system.  The final targeting data was given by TsAS-1 and PKU-1 control systems.  Any 100 mm (3.9") turret could provide firing data should the central computer be knocked out.

The mounting was cross-level stabilized up to -20/+20 degrees of roll using a Jenny-type coupling which was automatically controlled from a central location using the remote control system D-5S.  In 1949 a BL-127 quadruple mount was designed, but this was not approved for production.

Constructed of loose liner, casing, barrel nut and a support ring.  Used a sliding breech block with spring automatics.  The guns were not individually sleeved.
WNRussian_39-70_cm5_Sverdlov_pic.jpg

100 mm/70 (3.9") mounts on a Sverdlov Class Cruiser
Photograph from "Light Cruisers of the Chapaev and Sverdlov Class"
WNRussian_39-70_cm5_crew_pic.jpg

100 mm/70 (3.9") side view
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Gun Characteristics
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Designation 100 mm/70 (3.9") CM-5
Ship Class Used On Chapaev and Sverdlov classes
Date Of Design 1947
Date In Service 1949
Gun Weight 3.91 tons (3.972 kg)
Gun Length oa 276.18 in (7.015 m)
Bore Length 261.22 in (6.635 kg)
Rifling Length 227.4 in (5.776 m)
Grooves 32
Lands N/A
Twist N/A
Chamber Volume 640.7 in3 (10.5 dm3)
Rate Of Fire CM-5-1:  15 - 18 rounds per minute
BL-127:  16 - 18 rounds per minute
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Ammunition
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Type Fixed
Weight of Complete Round N/A
Projectile Types and Weights HE (F-55) - 34.39 lbs. (15.6 kg)
FRAG (OF-55) - 34.39 lbs. (15.6 kg)
AA (ZS-55) - 34.39 lbs. (15.6 kg)
AA (ZS-55P) - 35.05 lbs. (15.9 kg)
Star Shell (SB-55) - 32.67 lbs. (14.82 kg)
ECM (anti-radar) (PB-55) - 39.19 lbs. (14.6 kg)
Bursting Charge HE (F-55) - 2.47 lbs. (1.12 kg)
FRAG (OF-55) - 2.78 lbs. (1.26 kg)
AA (ZS-55) - 2.95 lbs. (1.34 kg)
AA (ZS-55P) - 19.44 lbs. (8.816 kg)
Star Shell (SB-55) - 0.086 lbs. (0.039 kg)
Projectile Length N/A
Propellant Charge Full (ZhB-55PB) - 15.87 lbs. (7.2 kg)
Reduced (AUM-55PB) - 8.6 lbs. (3.9 kg)
Special (ACB-55PB) - 9.04 lbs. (4.1 kg)
Muzzle Velocity FRAG (OF-55)  - 3,281 fps (1,000 mps)
AA (ZS-55) - 3,281 fps (1,000 mps)
AA (ZS-55P) - 3,264 fps (995 mps)
Star Shell (SB-55) - 2,559 fps (780 mps)
ECM (anti-radar) (PB-55) - 2,575 fps (785 mps)
Working Pressure Full (ZhB-55PB) - 22.8 tons/in2 (3,600 kg/cm2)
Reduced (AUM-55PB) - 12 tons/in2 (1,900 kg/cm2)
Special (ACB-55PB) - 14.6 tons/in2 (2,300 kg/cm2)
Approximate Barrel Life N/A
Ammunition stowage per gun 320 rounds
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Range
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Elevation With 34.39 lbs. (15.6 kg) FRAG (OF-55) 
Range @ 49 degrees 26,460 yards (24,200 m)
Elevation With 34.39 lbs. (15.6 kg) AA (ZS-55) 
Range @ 30 degrees 
(Max. Range using Time fuze)		 23,400 yards (21,400 m)
Max. Effective ceiling 52,490 feet (16,000 m )
Max. Ballistic ceiling 65,620 feet (20,000 m)
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Mount / Turret Data
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Designation Twin Turret:
  Chaepev (4):  CM-5
  First four Sverdlov class (6):  CM-5-1
  Later Sverdlov class (6):  CM-5-1bis

Quadruple Mount:  BL-127
Weight CM-5-1:  45 tons (45.8 mt)
BL-127:  65 tons (66 mt)
Elevation CM-5-1:  -8 / +85 degrees
BL-127:  -5 / +85 degrees
Rate of Elevation CM-5-1:  16 degrees per second
BL-127:  20 degrees per second
Train CM-5-1:  -200/+200 degrees
BL-127:  320 degrees
Rate of Train CM-5-1:  17 degrees per second
BL-127:  30 degrees per second
Gun Recoil CM-5-1 @ 0 degrees:  19.6 in (49 cm)
CM-5-1 @ 85 degrees:  22.8 in (58 cm)
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Data from
"Jane's Pocket Book 9:  Naval Armament" edited by Denis Archer
"Entsiklopedia Otechestvennoi Artillerii" (Encyclopedia of Fatherland (Russian) Artillery) by A.V. Shirokorad
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Special help from Vladimir Yakubov