1. Barrel. Assembled— Trunnion ring. Gas nozzle ring. Orifice screw. Gas cylinder support. Front sight carrier. Front sight. 2. Regulator. 3. Receiver. Assembled— Bottom plate. Front feed guide. Rear feed guide. Cartridge base stop. Feed piece cover. Closing spring. Rear sight base. Rear sight screw. 4. Hand guard. Assembled— Catches for legs. Catch springs. 5. Locking nut. 6. Locking screw. 7. Cocking handle. 8. Guard with stock. Assembled— Recoil spring seat. Hinged strap. Elevating screw tube. Elevating screw slide. Slide spring. 9. Barrel rest. 10. Elevating mechanism. Assembled— Outer screw. Inner screw. Base. 11. Piston. 12. Fermeture nut. 13. Breech block. 14. Extractor. 15. Firing pin. 16. Ejector. 17. Ejector cap. 18. Cartridge stop. 19. Cartridge stop holder. 20. Sear. 21. Trigger. 22. Feed piece. 23. Feed spring. 24. Recoil spring. 25. Ejector spring. 26. Sear spring. 27. Cartridge stop spring. 28. Extractor spring. [Illustration: Plate X. Infantry Model with Elevating Gear. ] [Illustration: Plate XI. External Parts. ] [Illustration: Plate XII. Working Parts. ] ACCESSORIES. One dismounting wrench. One ejector key. One hand extractor. One cleaning rod complete. Two wire brushes. One cleaning brush. One gas cylinder cleaner. One oil can. One front sight cover. GENERAL DESCRIPTION. The gun comprises a single barrel, receiver, guard and stock, rigidly assembled. Guided in the receiver, parallel to and below the barrel, is the piston, which by its reciprocating motion assures the automatic action of the gun. This reciprocating motion is brought about as follows:—When the bullet in its passage through the bore has passed a port connecting the bore with the gas nozzle, a small portion of the powder gas issues from the nozzle, and impinging in the cup-shaped forward extremity of the piston, throws in the rear. The recoil spring compressed by the piston in its rearward movement now returns the piston to its initial position. In its movement to the rear the piston, which is accompanied by the breech block, opens the breech, extracts and ejects the spent cartridge case, and brings a fresh cartridge to the loading position. In its forward movement the breech is locked and the shot fired. Feed. The cartridges are fed into the gun on flat, tempered steel strips, of 30 rounds each.