GB586749A - Improvements in or relating to ordnance and small arms - Google Patents

Abstract

586,749. Non-recoil guns. BURNEY, SIR C. D. Dec. 5, 1941, Nos. 15718/41 and 6171/42. [Classes 9 (i), 92 (ii) and 119] In order to eliminate recoil and enable a gun of relatively large calibre to be fired from the shoulder or from a light field carriage or naval mounting, the gun has an extension in rear of the cartridge chamber 2, Fig. 2, formed by a breech chamber 3 which provides a space between the cartridge chamber and one or more rearwardly-directed gas-discharge nozzles 7. The cartridge chamber may be laterally disposed as shown in Fig. 8. The gas chamber may be provided in a hinged breech-block x which is rotated for locking and swung down about a pivot 5, Figs. 2 and 6, or the breechblock may be swung aside about a longitudinal pin 54, as shown in Fig. 9. The nozzle throat area is so related to the cross-sectional area of the barrel that 50 per cent or more of the gases are discharged rearwardly, a relatively large charge of propellant being used. The gases on their way to the nozzle or nozzles pass through a grid 6, preferably of conical form, and an adjustable valve 8 is provided to regulate the area of the gas-discharge opening. Figs. 1 and 2 show the invention applied to an antitank rifle fired from the shoulder and having a pistol-grip 11 and shoulder-piece 14. The trigger 12 is connected by a Bowden wire 13 to a lever 16, Fig. 6, controlling a sear 19, engaging a bent 21 in a spring striker 23, cocked by a stirrup when the breechblock is swung open. The striker engages a lever 26 connected to a firing-pin 28. The lever 16 engages the breechblock to lock it at the instant of firing. A pivoted cartridge-extractor is actuated during the opening of the breech. The muzzle is perforated and surrounded by a conical casing 98, open at the front to relieve the gas pressure on the projectile before it leaves the muzzle. The tapered cartridge case has a thick metal wall with a thin metal foil base readily disrupted or consumed when the charge is ignited. In the modification, shown in Fig. 8, the side walls of the cartridge are disruptible and the end walls are made relatively thick. In the form shown, in Fig. 9, the gun is a low pressure one for firing bombs and is fired from the shoulder or as a mortar. The breech-block carries a number of nozzles 67, the central one 68 being adjustable. The block is mounted on a sleeve 54, rotatable on the barrel. Within the sleeve is mounted the spring firing-rod 55, having rollers 65 engaging a cam 66 to cock the rod on to a sear 57 when the breech is closed. On releasing the sear the rod 55 engages a lever 52, carrying the 'firing-pin. The breech-block is released for opening by operating a catch 43 by a lever 46 in a hand grip 48, the catch acting through a rod 49 to block the firing-pin when the-breech is open. Fig. 13 shows a modified form of breech block suitable for a high velocity field gun, the block 75 being loaded with fixed ammunition after swinging it transversely on pivots 79 by a handle 81. The pivots carry cams for operating the extractors.