133,351. Imray, O., (Colt's Patent Fire Arms Manufacturing Co.). May 21, 1917. Machine guns.-Relates to recoil-operated guns of the kind described in Specifications 14921/00 and 133,329, and consists mainly in arranging the firing-pin and main spring in the breech-bolt in conjunction with a cocking-lever pivotally attached to the breechbolt. As shown in Fig. IV., the firing-pin comprises a tubular body S sliding within the brerechbolt E and formed with an eccentric firing-point S<2>. The main-spring T is confined within the firing-pin by a. transverse pin S<3> and by a cotter s, which also carries a blade spring for the sear V. This slides vertically at the end of the breachbolt, and has a forward tooth v<1> adapted to catch a bent s<1> in the firing-pin, and a slotted lower end v<2>, Fig. V., adapted to ride along the trigger W, Fig. I. Bevelled lugs on both sides of the front end of the trigger engage corresponding bevelled ledges in the slot of the sear to depress the sear when the trigger is pulled in the first instance, and again to wedge the sear down on the return stroke if the trigger is still pulled for firing bursts automatically. The firing-pin is cocked during recoil by a lever U pivoted at u to the breech-bolt and fitting into a bevelled slot in the top plate H. The trigger W may be locked at safe by a transversely-sliding catch w carried by the rear plate J, and this catch may itself be held in the unlocking or locking position by a spring plunger also carried by the rear plate J.