GB736839A - Improvements in or relating to cartridge shell making processes - Google Patents

Abstract

736,839. Making cartridge cases. REMING- TON ARMS CO., Inc. Sept. 25, 1953, No. 26517/53. Classes 83(2) and 83 (4). Extruding; pipe-end closing.-A cartridge case, preferably of aluminium, is made by producing by extrusion a thin-walled tube 23, Fig. 2, having an external enlargement 30 at one end, radially contracting the thickened end of the tube so as to transfer the enlargement 30 to the inside of the tube thereby forming a constriction 43, Fig. 7, and heading the tube at the thickened end. An aluminium slug 22 is inserted in a closed-ended die 15, Fig. 1, having a tapered side wall 18 and a counterbore 20, and is extruded rearwardly by a punch 25 to form the tube 23. The billet has a conical recess 24 which co-operates with the conical end 25<SP>1</SP> of the punch for centring the billet and also holds lubricant. The punch has a cylindrical land 26 and a tapering skirt portion 27. The extruded tube 23, Fig. 2, has a cylindrical bore and a slightly tapered external surface. After extrusion the conical end 34 of the tube is cut off by a rapidly rotating saw. The tube is then forced axially through a die 36, Fig. 7, having a tapered bore 37 and a bell mouth 37<SP>1</SP>. This operation is performed in three stages using three punches, such as 42, of different diameters so as to partially close the end of the tube at 43. The tube is then supported in a heading die and a punch is moved into the open end of the tube to engage the constriction. A heading tool then acts on the thickened end of the tube to form the head with the primer pocket 47, flash hole 48 and extraction rim 49, Fig. 10. During the heading operation the circumferential wall at the head part is tapered to correspond with the tapering outer surface, produced during extrusion, of the remainder of the case.