The breeching is of three kinds: the common; the chamber, plug, or mortar, [fig. 397.]; and the patent, [fig. 398.] The common was formerly used for soldiers’ musquets and inferior pieces. The second is a trifling improvement upon it. In the patent breeching, the screws do not interfere with the touch-hole, and the ignition is quicker in the main chamber.
The only locks which it is worth while to describe are those upon the percussion principle, as flint locks will certainly soon cease to be employed even in military musquets. Forsyth’s lock ([fig. 399.]) was an ingenious contrivance. It has a magazine a, for containing the detonating powder, which revolves round a roller b, whose end is screwed into the breech of the barrel. The priming powder passes through a small hole in the roller, which leads to a channel in communication with the chamber of the gun.
The pan for holding the priming is placed immediately over the little hole in the roller. There is a steel punch c, in the magazine, whose under end stands above the pan, ready to ignite the priming when struck upon the top by the cock d, whenever the trigger is drawn. The punch immediately after being driven down into the pan is raised by the action of a spiral spring. For each explosion, the magazine must be turned so far round as to let fall a portion of the percussion powder into the pan; after which it is turned back, and the steel punch recovers its proper position for striking another blow into the pan.
The invention of the copper percussion cap was another great improvement upon the detonating plan. [Fig. 400.] represents the ordinary percussion lock, which is happily divested of three awkward projections upon the flint lock, namely, the hammer, hammer spring, and the pan. Nothing now appears upon the plate of the lock, but the cock or striking hammer, which inflicts the proper blow upon the percussion cap. It is concave, with a small metallic ring or border, called a shield or fence, for the purpose of enclosing the cap, as it were, and preventing its splinters doing injury to the sportsman, as also protecting against the line of flame which may issue from the touch-hole in the cap nipple. This is screwed into the patent breech, and is perforated with a small hole.