CHAPTER VII.
75-MM. FIELD GUN MODEL 1916.
THE GUN.
| Weights and Dimensions. | |||||
| Weight | Kg | 339.74 | pounds | 749. | |
| Caliber | mm | 75. | inches | 2.953 | |
| Total length | mm | 2,308.5 | inches | 90.9 | |
| Length of bore | mm | 2,134. | inches | 84. | |
| Length of rifled portion of | |||||
| bore | mm | 1,847. | inches | 72.72 | |
| Number of grooves | 24 | ||||
| Width of grooves | mm | 7.30 | inches | .2874 | |
| Depth of grooves | mm | .501 | inches | .02 | |
| Width of lands | mm | 2.52 | inches | .0992 | |
Twist, right hand, zero turns from origin to a point 2.89 inches from origin. Increasing from one turn in 119 calibers at a point 2.89 inches from origin to one turn in 25.4 calibers at a point 9.72 inches from muzzle. Uniform from a point 9.72 inches from muzzle to the muzzle.
Description of the 75-MM Field Gun.
The gun is built up of alloy-steel forgings, consisting of a tube, jacket, breech hoop, and clip. All of the parts are assembled with a shrinkage.
The tube extends from the muzzle to the rear end of the powder chamber and two recesses are cut in its rear face to form seats for the lips on the extractors.
The jacket is assembled over the muzzle end of the tube. The jacket carries two flanges on its lower side, which form guides for the gun in the cradle of the carriage, and a lug on top near the forward end which contains a T slot, which holds the recoil cylinder in place. The rear end of the jacket is threaded on the outside to receive the breech hoop.
The breech hoop is threaded at its forward end and screws on to the rear of the jacket. The breech ring carries a recoil lug at the top for the attachment of the hydraulic recoil cylinder, and another lug at the bottom for attachment of the two spring piston rods. The rear part of the breech hoop is cut away to form the breech recess.
The clip is a short hoop shrunk on the tube near the muzzle. It carries two lugs on its under side which form guides for the gun in the carriage.