Hold gun with slot in receiver upward. Insert bolt, front end first. Replace slide, pushing to rear as far as it will go. Replace bolt pin, pushing it in as far as it will go by using end of handle lock. Replace belt guide and screw, having locking screw engage groove in belt guide screw. Replace carrier, having flat side or bottom up and carrier dog down. Insert pin. Replace gas lever, having piston drop into hole in gas cylinder. Adjust gas lever until large pin holes in gas lever and gas lever bracket are opposite each other, then insert gas-lever bracket pin. Next place retracting spring tubes in position having slot in followers align with long slot in retracting spring tubes. Force follower over projecting end of retracting connection by pressing follower end inward, at the same time slightly compressing retracting springs until pilot at end of tube clears bracket. Press tube inward at bracket end and into hole for pilot. Place bottom plate in position by putting tongue at rear end in receiver first and flush with rear end of receiver. Place safety in position. Right-hand side plate should be next placed in position, taking precaution to have slide pushed to rear as far as it will go and the feed lever on plate carried to rear as far as it will go, so that feed lever will lay between projections on slide when plate is in position. To place plate in position, have the dowel at rear of plate enter hole for same, in receiver, at the same time having groove near edge of plate engage rib on bottom plate and gas lever bracket pin enter hole in front end of plate. Turn gun over to rest on plate, draw slide forward, having slot at forward end of slide engage end of gas-lever connection. Hold gun at rear end with right hand to prevent moving. Take hold of gas-lever pin with the left hand and swing gas lever outward until slide pin can be pushed into hole in slide through gas-lever connection, having flattened end of slide pin enter slot in side plate. Place trip in holes and slot in receiver. Place left-hand slide plate in position by the same method as right-hand plate. Place side plate screws into holes in front and rear of side plates. If screws do not enter freely see that bottom plate is flush with rear of receiver; if not, tap bottom plate gently on front end until it is flush with rear end of receiver. Screw plates together and lock with locking screws, making a quarter turn of these screws to engage grooves in side plate screws. Push handle into hole in rear of receiver and lock with handle lock. Handle lock is placed in position by inserting large end into hole with the stem held upward and then turned toward front and downward to have projection engage locking cut in side plate and until handle lock stop springs over stem. Place gun in mount and run a few cartridges in a belt through gun to see that mechanism works properly. Keep hand away from trigger during this latter