| Weight of gun | 788 lbs. |
| Calibre | 3 inches |
| Length | about 7 feet |
| Number of lands and grooves | 24 |
| Muzzle velocity | 1700 ft. sec. |
| Maximum pressure per sq. in. | 33,000 lbs. |
| Limit of depression | (90 mils.) 5 degrees |
| Maximum elevation | (265 mils.) 15 degrees |
| Maximum range, trail sunk, about | 8,500 yds. (5 M) |
| Range at 15° elevation (265 mils) | 6,000 yds. (3½ M) |
3 Inch Field Gun, Models of 1904 & 1905.
Breech Mechanism Assembled.
Nomenclature of parts of Gun:—
- Jacket.
- Locking hoop.
- Tube.
- Bore.
- Rifling.
- Lands.
- Grooves
- Breech recess.
- Front clip.
- Muzzle.
- Dust guard.
- Recoil guides or clips.
- Chamber.
- Recoil lug.
- Line sight (front and rear).
- Handy oilers.
THE BREECH MECHANISM.
The breechblock is of the interrupted-screw type, and is provided with four threaded and four slotted sectors. The front end of the axial recess in the block is closed by a bushing. Four ventholes lead from a cavity in the bushing and permit the escape of gas to the rear in case of a ruptured primer. On the rear face of the breechblock are cut gear teeth, in which the gear teeth of the operating lever bevelgear mesh. The breechblock is concentrically mounted on a hub on the block carrier, in which the firing-lock case is fitted. Its position in the breech of the gun with reference to the axis of the bore is eccentric.
The breechblock is closed or locked by a continuous movement of the operating lever. When the block is swung to the closed position the front face of the block latch comes in contact with the rear face of the breech of the gun, thus forcing the latch out of the notch in the breechblock and back into a recess in the carrier. By continuing the motion of closing the mechanism, the breechblock is then rotated on the hub of the carrier and its threads engage with corresponding ones in the gun. When the breechblock is in the closed position, a lug on the firing-lock case serves to lock the carrier to the breechblock and prevents displacement due to a blowback.
The firing mechanism belongs to that type known as a continuous-pull mechanism; that is, no cocking of the firing-pin is required.