THE GARDNER GUN (CAL. 0.45″). [Illustration: FIG. 94.] Weight of gun 142 lbs. " " " and carriage 502 " Shots per minute 357 This gun consists of two breech-loading rifled barrels, _a_ (Fig. 95), (chambered at the rear to admit a flanged centre-fire metallic cartridge), having their axes in the same horizontal plane enclosed and supported in a bronze casing. The two openings in the front part of this casing are for the circulation of air to keep the barrels cool. The barrels are without motion, and are loaded and fired by the action of the breech mechanism, which is contained in the rectangular rear part of the casing. This is closed at the top by a hinged cover, _c_, which is firmly locked in position by screwing up the cascable. [Illustration: FIG. 95. _a._ barrels. _b._ casing. _c._ breech-cover. _d._ locks. _e e′_. cams. _f._ ejectors. _g._ feed. _h._ main spring-compressor. _i._ cocking-cam. _j._ cocking-lever. _l._ feed-valve lever. _v._ feed-valve. ] [Illustration: FIG. 96.] Motion is given to all the parts by the cams (_a_, Fig. 96), which are attached to the three steel disks, _b_, at opposite extremities of a diameter, and the whole is rotated around an axis, _c_, by means of a crank, _d_. The parts _abc_ form the main crank, which is supported in journal-boxes that are locked into the body of the rear case as shown in Fig. 95. [Illustration: FIG. 97.] The =Lock= (Fig. 97) in form resembles the letter U, having an extension from its side which contains the firing-pin, _h_; the mainspring, _i_, whose ends abut against the collar, _k_, on the firing-pin, and the sector-sleeve, _l_, which slides over the firing-pin; the sector or spring-compressor, _n_; the extractor, _b_; the sear, _e_; and the sear-spring, _j_. The U part of the lock, that works under and around the cam, is curved at the inner front to correspond with the outer circle of the cam, the office of the curved front being to hold the lock in position for firing. The circular firing-pin is flattened a portion of its length near the front end, to allow it to pass under the extractor, by which it is held in position. It extends from the head of the lock through the mainspring and sector-sleeve, terminating in a head, _m_, for locking into the sear. The sear, _e_, pivoted in the centre of the lock, holds the firing-pin securely, and prevents it from touching the cartridge until it is released from its hold by the action of the cam, when the lock is in its extreme forward position. The sector or spring-compressor, _n_, hinged in a recess of the lock, and engaging, by means of gear-teeth, with the sector-sleeve, _l_, has its arm, _g_, forced against the safety-stop, _o_, as the cam advances, thus compressing, through the medium of the sector-sleeve, the mainspring, and holding it tense until released by action of the sear.