Handbook for Light Artillery

by A. B. Dyer

The Latch-groove ([Fig. 31]) is in two parts, one longitudinal (d), at the front end of the block, and the other transverse (a), at the rear end. The stem of the latch drops into the front groove (e) when the block is withdrawn, and into the rear groove (b) when the block is revolved into its firing position, in each case unlocking the carrier-ring from the jacket—in the first case, so that it maybe swung back; in the second, to prevent the breaking of the latch when the gun is discharged.

The Locking-recess (e) is at the front end of the longitudinal latch-groove. The stem of the latch drops into it when the block is withdrawn, and thus locks the block positively to the carrier-ring.

The Guide-groove is the cylindrical recess at the rear of the block in which the guide-sectors move when the block is rotated.

THE CARRIER-RING.

Fig. 32.

The Guide-sectors (b, [Fig. 32]) are three projections from the interior of the carrier-ring (h), which fit in the slotted sectors of the breech-block and guide it during its motion through the carrier-ring.

The Latch-cover (i) is a separate piece which covers the latch and its spring, and is secured to the carrier-ring by two screws (j). On removing this plate the latch and spring can be taken out.

The Latch (f in [Fig. 32]) fits in a recess in the carrier-ring on the right side. It is acted on by a spring (b, [Fig. 33]), which pushes it constantly toward the axis of the carrier-ring. Its inner end or stem (a) rests on the surface of one of the slotted sectors, except at the end of its travel, when it drops into the corresponding recess in the block. As long as its stem rests on the surface of the sector its outer end or nose projects beyond the exterior surface of the carrier-ring, and, entering a recess in the jacket, locks the carrier-ring to the jacket. When the stem drops into its recesses, the nose of the latch is withdrawn by the action of the spring and the carrier-ring is unlocked. The front face of the latch has a recess (h), into which fits a hardened stud (s) that is screwed into the rear face of the jacket. This stud acting against the recess lifts the latch out of its locking-recess in the breech-block, and holds it in a position such that the stem can pass up the inclined groove. In order that the stud may act on the latch, a hole (g) is drilled through the front face of the carrier-ring for the stud to pass through.