Tag Archive for '120mm'

12 cm s. Gr. W. 42: Mortar

12 cm s. Gr. W. 42: German Heavy Mortar 120mm WW2

The Gr. W. 42, now being manufactured in Germany, closely resembles the Russian 12 cm mortar after which it is modeled. This weapon is of conventional design, consisting of a tube, base plate, and bipod. The bipod is clamped to the center base of the tube; the base of the tube fits into the circular base plate by a ball and socket joint. Elevating and traversing gears are operated in the usual way by small handles located at the top of the bipod.

The mortar may be either percussion or trigger-fired. The trigger mechanism can be set at “Einzel-Feuer”—single shot, or “Dauerfeuer”—continuous fire.

A two-wheeled, rubber-tired carriage is used for transport. Hooks on the upper surface of the base plate engage with U-shaped pieces attached to the carriage, and a clamp secures the barrel to the trail of the carriage. The bipod is apparently carried clamped to the mortar ready for action.

Three types of high-explosive bombs are fired from the Gr. W. 42 as well as Russian ammunition captured by the Nazis.


Caliber         120 mm (4.7 ins.)
Weight in action 606.1 lb.
Weight (including carriage) 880 lb.
Length of barrel (including breech piece) 6.12 ft.
Length of bore (approx.) 5 ft.
Width of carriage 5 ft.
Range (maximum) 6,560 yds.
Elevation 45°-80°
Traverse         3½° right and left at 45° elevation

German: p. 106

120 mm, 45 Caliber, Naval Dual Purpose Gun, Type 10

120 mm, 45 Caliber, Naval Dual Purpose Gun, Type 10 (Japanese WWII)

The Japanese Type 10 dual purpose gun has a 45-caliber barrel of monobloc construction with uniform right hand rifling. A long, narrow rectangular projection on the bottom of the barrel slides in a groove in the sleeve type cradle, preventing the barrel from rotating. The bearing surface for recoil being the machined barrel surface. The cradle is mounted on a pedestal mount which permits a traverse of 360 degrees.

The elevating handwheel is on the right side of the mount, while the traversing handwheel is on the left. An auxiliary handwheel on the left side permits the piece to be elevated and traversed by the gunner. To compensate for muzzle preponderance, a spring pusher type equilibrator is used. The gun is well balanced, and exceptionally easy to elevate. The recoil mechanism is a hydrospring type, the two outside cylinders housing the counterrecoil springs, and the center cylinder the hydraulic mechanism. A semiautomatic horizontal sliding breechblock is used.

The mount is of riveted construction.


Caliber       120 mm (4.7 ins.)
Weight (firing position) 6,500 lbs.
Length (gun and mount) 19 ft., 6 1/2 ins.
Length (firing position)
Height (gun and mount) 7 ft., 8 1/2 ins.
Height (firing position)
Width (gun and mount) 7 ft., 1 in.
Length of tube 17 ft., 1 1/2 ins.
Length of rifling 14 ft., 9 1/2 ins.
Length, of chamber 29.5 ins.
No. of lands 34
Width of grooves 1/4 in.
De-th of grooves .050 in.
Width of lands 1/8 in.
Muzzle velocity (shell) 2,700 f/s
Max. range (horizontal) 17,000 yds.
Max. range (vertical) 32,800 ft. (fuze)
Rate of fire 10-12 rds.
Traverse 360°
Elevation 75°
Depression 10°
Length of recoil 19.3 ins.
Ammunition H.E. shrapnel; H.E. phosphorus
Wt. of projectile 45.75 lbs.

Japanese: p. 114.5 (August 1, 1945)

120 mm, 45 Caliber, 11 Year Type Gun

Japanese 120mm 45 Caliber 11 Year Type Gun

This gun is a naval coast defense weapon manufactured at Sasebo Arsenal. It uses semi-fixed ammunition. The barrel is of built-up construction with uniform right hand twist rifling. A manually operated, horizontal sliding block breech mechanism is used. It is unusual in that the block does not pass all the way across the rectangular breech ring. The rear of the breech ring is cut in a keyhole shape. The operator of the elevation handwheel may fire the gun by means of a lever mechanism, or it may be fired by a lanyard attached to the right side of the breechblock.

The recoil system comprises three cylinders, two located above and one below the barrel.

The mount consists of a rectangular upper carriage which is mounted on a pedestal normally embedded in a solid foundation. A traversing scale is located on the pedestal. The traversing handwheel is in a horizontal position with the vertical shaft engaging a series of gears in the base mount. Platforms attached to the upper pedestal are provided for the gun layers and move in traverse with the gun.

Fire control equipment is of the usual Japanese naval coast defense gun type.


Caliber      120 mm (4.72 ins.)
Weight (traveling position)
Weight (firing position)
Length of gun (overall)18 ft., 3 1/4 ins.
Length of tube 17 ft., 3 3/4 ins.
Height of gun 6 ft., 11 ins.
Height (firing position)
Width (overall)
Length of rifling 14 ft., 8 1/2 ins.
No. of lands34
Width of grooves
Depth of grooves
Width of lands
Muzzle velocity (H.E. shell)2,700 f/s
Max. range (horizontal)
Max. range (vertical)
Rate of fire
Length of recoil
Wt. of projectile (H.E.)44.75 lbs.

Japanese: p. 114.4 (August 1, 1945)