Patent GB-1011964-A (GB)
Title: Convertible gun
IPC: F41A11/00
Filed: 1963-04-29
Abstract: 1,011,964. Convertible gun. E. M. STONER. April 29, 1964, No. 17861/64. Heading F3C. A convertible gun may be converted from a rifle to a machine gun by disassembling the parts of the gun in rifle form and re-assembling some of those parts together with additional parts in order to effect the conversion. In the rifle configuration the gun comprises a receiver 14, Figs. 2 and 5, having an opening 94 in the lower portion thereof, a trigger housing 16, an adjacent magazine adaptor 18 demountable associated with the lower portion of the receiver, a barrel 22 and a stock 12 demountable secured to the front and rear of the receiver. The trigger housing 16 which is demountably secured by means of a pin 28 to the stock 12 includes a spring-biased hammer 42 pivoted at 44, maintained in an inoperative position by engagement of a sear 54 on the trigger 48 pivoted at 52 with a land 56 on the hammer 42. Also mounted on the pivot 52 is a sear 58 engageable with a detent 62 on the hammer and rotatable by a torsion spring 64. A spring- loaded U-shaped latch 76 engages slots 84 in the receiver to maintain it in operative relationship with the trigger housing. The receiver 14 is formed with a pair of oppositely directed flanges which are slidably engaged in corresponding grooves in the trigger housing 16. The catch 76 may be released by actuating the trigger rearwardly to move the pivoted sear 66 downwardly to depress the latch. A rear sight 24 having an eyepiece 108 which is mounted upon a windage adjustment screw 110 is mounted by means of a dovetail connection overlying an opening 98 in the receiver. A bolt carrier 120 is located in the receiver and houses a bolt 126 which is rotatable therein and has a head 128 protecting from the front thereof so that the dogs 132 may engage corresponding surfaces 134 of the firing chamber 136. A bolt actuator 140 is mounted in the carrier 120 and includes a pin 142 which extends into an inclined slot 146 formed in the wall of the carrier and has a roller 148 mounted on its outer extremity to engage the surface 152 of the receiver. A shell ejector 153 is mounted on the bolt and is biased outwardly by a compression spring 154. The bolt carrier is operatively connected to a gas energizable piston 156 located in a cylinder 158 by a link 164 connected to the rear of the piston-rod 166. The link and piston-rod are provided with a guide rod 174 and a compression spring 176 adapted to return the link and piston-rod to a position which will locate the carrier 120 in closed battery position. A depending arm 178 on the link 164 engages in a slot 181 in the wall of the carrier for actuation thereof during firing. A bank of springy metal washers are located in the carrier to absorb shocks. A cap 202 is mounted at the rear of the carrier 120 and carries guide rollers 208 adapted to engage guide surfaces 152 in the receiver 14. A firing- pin 220 is carried in the carrier 120 and is adapted to be projected through an opening 224 in the bolt by the hammer 42 on firing. The intermediate portion of the firing-pin is provided with an annular groove 227 enlarged at 228. A locking detent 192 of the same size as groove 227 projects into the portion 228 when the gun is in the configuration of a rifle which permits relative movement between the pin 220 and the carrier. A flat 234 on the head of the firing-pin engages a flat 214 of the opening in the cap 202 to prevent the pin rotating with respect to the cap. The magazine adaptor 18 is mounted on the land 238 of the trigger housing and by means of a pin 242 through the receiver. The magazine 20 is frictionally retained in the adaptor 18. The barrel 22 has a collar 248 threaded thereon which slidably co-operates with a bore 252 in the forward extremity of the receiver and is retained therein by a spring-loaded pivoted latch 262 engaging behind a. shoulder 256 on the collar. A foresight 26 is provided on the gas cylinder 158. The gun may be converted to a machine gun by disassembling the parts and inverting the receiver so that the opening 98, Fig. 10, is disposed adjacent the sear 66 which may engage a land 292 on the carrier 120. Prior to locating the receiver with the trigger housing the bolt carrier is removed from the receiver to permit the cap 202 thereon to be rotated which causes the firing-pin also to be rotated because of the engagement of flats 214, 234. The detent 192 is then located in the groove 227 to prevent relative movement of the firing-pin with respect to the bolt carrier. A heavy barrel 322 provided with a hand grip is located similarly to barrel 22 in the receiver and an automatic cartridge belt feed mechanism 330 is mounted upon the receiver 14. The rear sight 24 is mounted on the feed mechanism. The gas piston, piston-rod and link 178 act similarly as in the rifle configuration but the boltcarrier in contrast to the rifle action is maintained in the open battery position prior to firing by engagement of the sear 66 with the land 292. The firing-pin projects from the forward extremity of the bolt to fire a cartridge in the chamber 136 when the bolt-carrier approaches closed battery position. The beltfeed mechanism 330 comprises a channelshaped lever 344 pivoted at 343 which is engaged by the uppermost roller 208 of the cap 202 and includes an angularly bent forward extremity 346. The latter has an actuating arm and bracket 348 secured thereto which extends into engagement with a carriage 360 mounted on rollers 362 for movement on tracks 364. A guide roller 354 engages the underside of the cover 340. Mounted on the carriage 360 and biased downwardly by spring 372, Fig. 13, are cartridge-advancing dogs 374 which are adapted to reciprocate by movement of the carriage 360 to advance cartridges 376. A detent dog 382 is urged upwardly by a torsion spring 384 into engagement with an associated cartridge to prevent reverse movement of the belt. A spring-biased tongue 388 is mounted on the carriage 360 to force the cartridges downwardly into a position within the receiver in which they may be urged into the firing chamber 136. The machine gun will thus fire so long as the trigger is depressed, the boltcarrier reciprocating in the receiver. The guide roller 208 moving within the channel shape of the lever 344 causes the latter to pivot back and forth about the pin 343 and so causes the carriage to move back and forth to feed the cartridges.