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.
SPECIFICATIONS
| 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)