To Open the Breech.—Grasp the lever-handle (h, [Fig. 37]) with the left hand, thumb down, and raise it until it strikes the stop, then rotate the block as far as possible to the left; lower the lever-handle: its cam (d), acting against the surface (r) of the carrier-ring, will withdraw the gas-check if it sticks in its seat. This rotation of the block pushes the latch into its recess and locks the carrier-ring to the jacket. Grasp the bronze-handle (g) with the right hand, thumb to the right, and withdraw the block until it comes up against the stop. In this position the stem of the latch drops into the locking-recess, locking the block to the carrier-ring, and at the same time unlocking the carrier-ring from the jacket; swing the block and carrier-ring around to the left and insert the projectile and charge.
To Close the Breech.—Seize the bronze-handle with the right hand, thumb to the right, and swing the carrier-ring and block around until the carrier-ring is in its seat, grasping the lever-handle with the left hand, thumb down, at the same time, and raising the handle until it strikes the stop. The carrier-ring should be brought up to its seat sharply, but without slamming, and should be held firmly for an instant, otherwise the ring may start back slightly from the jar and the retracting-stud fail to hold the latch-pin high enough to allow the block to move forward.
When the carrier-ring strikes its seat the retracting-stud enters the hole in the front face of the ring, and, acting on the recess in the latch, lifts the latch to its travelling position, that is, lifts it out of the locking-recess and holds it in such a position that when the block is pushed forward, the lower end of the latch will strike the inclined surface at the front of the longitudinal groove.
Raise the lever-handle until it rests against the stop, and push the block forward until it stops. During this travel the lower end of the latch has moved up the inclined surface of the longitudinal groove and has locked the carrier-ring to the jacket.
Revolve the block one sixth of a turn until it strikes the stop; lower the lever-handle to its proper position, when everything will be in the condition first described, the vent will be uncovered, and the gun will be ready for firing.
When the block is revolved one sixth of a turn the lower end of the latch gradually drops into its groove, unlocking the carrier-ring, which remains so during firing.
INSTRUCTIONS FOR DISMOUNTING.
1. Raise the lever-handle and turn the breech-block to the left.
2. Take out hinge-pin screws and remove the hinge-pin.
3. Withdraw the breech-block with carrier-ring.