Patent GB-1167536-A (GB)
Title: Improvements in Automatic Guns
Inventor: STONER EUGENE MORRISON
IPC: F41A19/33
Filed: 1966-09-29
Abstract: 1,167,536. Automatic weapon. E. M. STONER. 29 Sept., 1966 [29 Sept., 1965], No. 43557/66. Heading F3C. An automatic weapon comprises a barrel 5, a receiver 6 and an ammunition feeding means 7 comprising two ammunition receiving openings one on each side of the receiver and an ammunition feed tray 228, 229 adjacent each opening. A carrier mechanism including a bolt carrier 29 and a bolt 28 is slidably housed within and resiliently urged towards the forward end of the receiver 6, the bolt carrier 29 consisting of an upper sleeve 31 within which the bolt 28 is housed and a lower body portion 32. The bolt 28 carries a spring-loaded extractor claw 168 and houses an ejector rod or pin 175 and a firing pin 173, the latter being secured to the sleeve 31. The bolt 28 is locked in its firing position by co-operating teeth 160, 161 (Fig. 21) of the breech and barrel respectively, the bolt 28 being rotated to bring about this co-operation by a cam follower attached to the bolt riding in a cam slot in the sleeve 31 (Figs. 15, 27, not shown) on relative movement between the bolt 28 and sleeve 31. The barrel 5 is mounted in the forward part 25 of the receiver for sliding recoil movement relative to the receiver. The recoil of the barrel is damped by a valved piston 75 which is connected to the barrel and which works in a liquid filled cylinder 70 against a recoil spring 98. The inner wall of the cylinder adjacent the piston 75 is provided with a tapering throttling groove (Fig. 3a, not shown) to regulate damping on recoil. In its recoil movement the piston 75 urges liquid forwardly to give an accelerator piston assembly 93 of which the piston 95 is of smaller diameter than the piston 75 a higher velocity than the recoiling barrel. The rearward end of the accelerator piston assembly strikes the lower body 32 of the bolt carrier 29 to urge the bolt carrier 29 rearwardly. Rearward movement of the bolt carrier initially unlocks the bolt 28 and the carrier mechanism recoils until it strikes a buffer assembly 38 to urge the ejector rod 175 forwardly and eject a cartridge through an opening 311. The buffer assembly 38 comprises a stack of Belleville springs which are mounted in such a way that they can be compressed by forces acting in a rearward or forward direction. The forward force is provided by a sear 41 mounted on the buffer assembly co-operating with a sear notch 42 on the bolt carrier 29. The sear forms part of a trigger mechanism 40. The initial cocking mechanism of the weapon comprises a block 207 which is spring loaded towards the forward end of the receiver 6 and which is connected to a chain 205. The chain 205 is engaged by a manually rotatable sprocket 215 such that on rotation of the sprocket in one direction the block 207 is moved against its spring loading towards the rear of the receiver 6 taking with it the carrier mechanism until the sear 41 rides into the sear notch 42 of the carrier mechanism. The two ammunition feeding trays 228, 229 (Fig. 21) are interconnected at their rearward ends such that one or other of the trays can be brought selectively into the ammunition feeding position or both trays can be held in a non-feeding position. The selection is achieved manually, a manually actuated arm resting in one of three notches formed on a bracket upon which the lever assembly forming the selection means is pivoted (Fig. 25, not shown). Further pivots are provided at the forward end of the feeding trays, the pivots comprising resiliently telescopic pins 219. Each feeding tray is provided with a pair of feed pawls 277 mounted on a slide, the slide being reciprocated in a vertical plane by a cam follower 270 connected to the slide working in a cam slot 271 in the carrier mechanism. Each tray also comprises a pair of ammunition retaining pawls (Figs. 22, 23, 25, 26, not shown). The ammunition is guided towards openings in the feeding trays and corresponding openings 265, one each side of the receiver 6, by spring plates 288 which are mounted on pivoted guide arms 291. The plates 288 and retaining pawls may be swung away from their normal positions manually such that ammunition belts can be disengaged from the feeding trays. The openings in the feeding trays are such that a cartridge partly projects into the line of action of the breech bolt 28, a positioning stop (295, Fig. 25, not shown), a ramp guide 299 and tapered surfaces 298 on the locking teeth 161 guiding the cartridge into the chamber of the barrel. The weapon may be mounted for elevation and training in a collar which in turn may be mounted on a vehicle (Fig. 1, not shown). The feeding tray selection means and the trigger mechanism may be incorporated in an electrical circuit such that the weapon may be fired by the closing of a switch and the feeding tray selection means determines whether the weapon is fired automatically or semi-automatically (Fig. 30, not shown). In a further embodiment the recoil damping and carrier mechanism accelerator means may comprise a spring-loaded piston which is connected to a lever which in turn engages the carrier mechanism (Fig. 29, not shown). A rear peep sight blade 256 is adjusted in a vertical direction according to the feeding tray in use by means of a cam follower 257 which works in a cam slot formed in a bracket 259. The bracket 259 comprises part of the feeding tray connecting means which moves laterally of the weapon on the change over from one feeding tray to the other.