254 mm/45 (10") Bofors
Updated 26 November 2008

Built by Bofors, these guns were mounted on Coastal Defense vessels.

Constructed of A tube, two part jacket and screwed-on breech piece.  Originally used a sliding horizontal breech mechanism but was later fitted with a conventional Welin breech mechanism.


Turrets for Väinämöinen in Bofors erecting shop
Photograph copyrighted by Bofors


Turret for Väinämöinen in Bofors erecting shop
Photograph copyrighted by Bofors


254 mm propellant casings

Gun Characteristics
Designation 254 mm/45 (10") Bofors
Ship Class Used On Väinämöinen class
Date Of Design about 1929
Date In Service 1932
Gun Weight 37.3 tons (37.9 mt) including breech mechanism
Gun Length oa 262.6 in (10.339 m)
Bore Length about 450 in (17.717 m)
Rifling Length N/A
Grooves N/A
Lands N/A
Twist N/A
Chamber Volume N/A
Rate Of Fire about 2 - 3 rounds per minute
Type Separate
Projectile Types and Weights APC - 496 lbs. (225 kg)
Bursting Charge N/A
Projectile Length N/A
Cartridge Case Type, Size and Empty Weight probably brass, size N/A, 99 lbs. (45 kg)
Propellant Charge 154 lbs. (70 kg)
Muzzle Velocity 2,789 fps (850 mps)
Working Pressure N/A
Approximate Barrel Life N/A
Ammunition stowage per gun N/A
Elevation With 496 lbs. (225 kg) AP Shell
Range @ 45 degrees 33,140 yards (30,300 m)
Mount / Turret Data
Designation Twin Mounts
   Väinämöinen (2)
Weight  252 tons (256 mt)
Elevation -10 / +45 degrees
Elevation Rate N/A
Train about +150 / -150 degrees
Train Rate N/A
Gun recoil 26.6 in (67.5 cm)
Loading Angle 0 degrees
Note:  The turret was on a ball track and was electrically powered with hydraulic drive for training and elevation.  Guns were individually sleeved but could be coupled together.
Data from
"Naval Weapons of World War Two" by John Campbell
Off-site Resources

Kosaku Ariga (Jarek) website