US3128670A - Flashless non-recoil gun and round - Google Patents

Description

April 14, 1964 L. v. S'BLACKER FLASHLESS NON-RECOIL GUN AND ROUND Filed Oct. 9. 1961 2 Sheets-Sheet l April 14, 1964 v. s. BLACKER 3,128,570

FLASHLESS NON-RECOIL GUN AND ROUND Filed Oct. 9, 1961 2 Sheets-Sheet 2 IQN'" 35235332 ATTORNEY United States Patent 3,128,670 FLASHLESS NON-RECOEL GUN AND ROUND Latham Valentine Stewart Blacker, Coldhayes, Liss, England Filed Get. 9, 1961, Ser. No. 143,700 2 Claims. (Cl. 89-11) This application is a continuation-in-part of my application Serial No. 528,975, filed August 17, 1955, now abandoned.

The requirements to be met by a truly satisfactory antitank gun for use by infantry are very exacting. The gun must fire a projectile of substantial size, for example over 3 /2 lbs., yet the gun should if possible be sufficiently light to be carried by one man, and arranged to be fired from the shoulder by a prone manthat is to say it should not require a free-standing mounting. It follows that, even though high muzzle velocity is not required, because the projectile will be of the hollow charge or squash head type, the muzzle energy required is substantial, and yet recoil on the firer must, at least to a large degree, be avoided. Attempts have been made to achieve this by discharging rearwards from the gun either gas, or small shot, or a counter projectile.

In assessing the success of these attempts, further factors must be taken into account. One is that it is a very serious matter if an infantryman reveals his position to the enemy. A gun which relies on rearward discharge of gas must have a large charge, to produce sufficient rearward momentum of gas to counter the momentum of the substantial projectile. The result is the emission of smoke, and even worse of a great flash of flame, which reveals the position of the gun even if the gun and its firer are themselves concealed. This is most dangerous for the user and for friendly troops in the vicinity. grettable that, in the absence of anything better, various armies are today equipped with weapons which emit such a flash.

Furthermore a direct rearward flash is dangerous to friendly troops in rear of the gun, and direct rearward discharge of small shot or of a solid projectile is much more dangerous. No doubt for this reason the Davis gun, which discharged small shot directly rearwards, although proposed initially as a piece of ordnance, Was used successfully only as an aircraft weapon, around the year 1916, rearward discharge of shot being not considered dangerous in the air.

The Burney gun, proposed in about 1942, but never to my knowledge used practically, had a rear barrel inclined at an obtuse angle to a front barrel, the rear barrel terminating in a set of nozzles for discharge of gas. This would in no way reduce the dangerous flash. In fact the inclination of the rear barrel was proposed solely to enable the front barrel to be elevated without the rear barrel striking the ground.

I have discovered that it is possible to construct a gun which can be loaded with a unitary round including a front projectile, a propellant charge, and a rear quantity of small shot, and which will discharge the small shot in a direction at an obtuse angle, of the order of 150, to a front barrel. Experience with shot guns shows that if the degree of contraction of a choke barrel exceeds a very small amount (e.g. 0.040 inch in a twelve bore gun) the shot will jam in the barrel. Consequently it is far from evident that a quantity of shot starting from a position aligned with the projectile, as it necessarily is in a unitary round, can be caused to discharge at an obtuse angle. Nevertheless I attain this by using a rear barrel which has a substantially uniform cross section along its whole length and which has a curvilinear axis, which is in line at its front end with the axis of the front barrel and of a chamber into which the round is loaded, the chamber It is re- 0 3,128,670 Patented Apr. 14, 1964 and rear barrel being separable to permit loading of the round into the chamber.

Use is made of a relatively large projectile of hollow charge or squash head type and a relatively low charge. Consequently the pressure attained within the gun is fairly low and the gun may be correspondingly lightly constructed. Moreover, contrary to what might be expected, the curved part of the rear barrel does not become overstressed, nor does it become appreciably eroded internally, nor is the resistance to movement of the shot along the rear barrel so great as to be liable to break the connection between the chamber and the rear barrel. Any tendency to elastic deformation of the rear barrel, tending to straighten it during firing, is slight, and can be compensated for in the setting of the sights of the gun.

Since the projectile is relatively large, and" the maximum range at which a tank requires to be engaged is of the order of 1,500 to 2,000 yards, the trajectory of the projectile is nearly flat. A flat latter part of the trajectory is of importance to an infantryman, because it makes accurate estimation of the range of a target unnecessary. Particularly good results as to flatness of trajectory and lowness of maximum internal pressure in the gun are obtained with an unrifled front barrel and a projectile of good streamline shape having a tail with a drum-type stabiliser, or radial fins which are radially movable so as to fit within the barrel on firing, but to expand to a greater radius as soon as the round has left the gun.

The lowness of the maximum. internal pressure, and the fact that the gas evolved by the charge can be sealed between a gas check in rear of the projectile and a gas check in front of the small shot, means that the charge is very small as compared with that for guns which discharge gas rearwards, and the smoke and flash emitted are very slight and practically imperceptible.

With a flat trajectory, the gun is fired with the front barrel nearly horizontal, and consequently the shot is discharged obliquely upwards and rearwards at about 30 to the ground. It follows a curved trajectory upwards and then downwards, and encounters such great air resistance that it disperses and reaches the ground at non-lethal velocity. Consequently there is only a very small area immediately in rear of the gun that is dangerous to friendly troops.

In order to assist the maintenance of uniform muzzle velocity with successive projectiles, the two gas checks may be connected by a tie so that on firing there is confinement of the charge until the tie is broken by a substantial rise in gas pressure.

The accompanying drawings show an example of a gun and round according to the invention. In these drawings:

FIGURE 1 is a longitudinal section of the gun, loaded with a round;

FIGURE 2 is a longitudinal section of part of the gun and round on a larger scale.

The gun includes a straight front barrel 2 and chamber 4 in one piece, the bore of the chamber being slightly greater than that of the front barrel, together with a rear barrel 6 which is curved in the part of its length nearest the chamber, through an arc of about 30, and possibly stiffened by a web 7. The rear barrel is supported by a leg 8 and a foot 10, and is steadied and aimed by a prone man by means of a shoulder piece 12 and a handle 14.

The outer straight ends 15 and 17 of the front and rear barrels can be unscrewed to reduce the bulk of the gun for carriage.

The projectile 1 consists of a head 16, tubular tail 18, and drum or cuff type stabilizer 20 on the end of the tail, and is driven by a gas check 22 having a spigot 24 which fits into the tail and which is jettisoned by a small charge 23 after the projectile leaves the gun. A safety collar 25 is in fact removed before loading. A quantity of small shot 26 is housed in a thin metal casing 28, which carries the second gas chesk 30. The centres of the gas checks are connected by a perforated brass tube 32 which acts as the frangible tie and which houses an electrically-fired primer 38. The main charge (which is omitted from FIGURE 2 for clarity) lies in the space 36 around the tube.

The tube 32 can readily be made to exert a substantial degree of confinement to a good degree of accuracy. Moreover the breaking strength of the tube can easily be adjusted by varying the size of the perforations. Consequently a good level of uniformity may be obtained in the behaviour of successive rounds, which means that once the sights of the gun are set it will hit a target accurately.

The casing 28 has a rear cover 29 lightly soldered on, and includes a parachute 31 which is separated from the small shot 26 by a wad 33 and is connected to the front of the casing by a rod 35. On firing, the casing bursts to release the small shot and is itself lowered harmlessly by the parachute. Alternatively the casing may disintegrate. The shot is not only retarded by air resistance, but also somewhat dispersed.

The passage of the casing and shot round the curve in the rear barrel does not lead to any jamming or to appreciable erosion of the barrel wall. It seems probable therefore that the casing and the shot within it deform somewhat in a ductile manner as they pass round the curve.

One lead 38 from the primer goes to the tube 32 and is thus connected, by contact of metallic parts, to the barrel of the gun, While the other lead 40 goes to a contact ring 42 of metal foil mounted on a ring 44 of insulating material which fills a gap between the rims of the gas checks. These rings disintegrate or are burnt away on firing. The contact ring engages a plunger 46 which extends through an insulating bush 48 in the Wall of the chamber. The plunger and barrel are connected to a magneto operated by squeezing a front part 50 of the handle 14.

The disintegration of the rings 42 and 44 means that there is nothing to be extracted from the gun after firing. That is to say, the round is devoid of anything in the nature of a cartridge case.

The chamber and front barrel can be disconnected from the rear barrel while remaining supported in a ring 51 carried by arms 52 and 54 of a bracket extending forwards from the rear barrel. The rear of the chamber has an external interrupted thread 58 in a socket 59 on the forward end of the rear barrel. Just in front of the thread the socket is enlarged and houses a U-sectioned flexible brass sealing ring 60, and a rigid guide ring 62. These cooperate with a cylindrical surface 64 on the chamber.

In loading, the front barrel and chamber, on being released from the socket by a quarter turn, are slid forwards in the ring 51 until the rear end of the chamber is clear of the socket, and then swung about pins 66 until the rear end of the chamber is sulficiently offset from the socket to permit a round to be inserted. The movements are then reversed and the gun is ready to fire. A contact 68, on an insulated mounting on the arm 54, makes con- ,tact with the outer end of the plunger 46 in the wall of the chamber when the front barrel and chamber are fully screwed home, thus completing the firing circuit from the l magneto.

The plunger 46 is urged outwards by a light spring 70, so that it does not obstruct the barrel during loading. The contact 68 is urged inwards by a stronger spring 72 which urges the plunger inwards against the contact ring 42. When the gun is fired, the gas pressure forces the plunger outwards against the spring 72 until a conical part '74 seals against a seat in the insulating bush 48 so that escape of gas is prevented.

The projectile, by reason of its favourable shape for air flow and its tail stabilizer, does not need a high velocity, but will travel in a nearly flat trajectory with a relatively head of a kneeling man. Consequently the sole danger in rear of the gun is to a man standing upright directly behind the gun within 2 or 3 yards of the rear muzzle.

Guns and rounds according to the present invention may of course be made in a variety of sizes, but details of one typical example are given below by way of illustration of the success achieved by the invention in meeting the requirements for a truly satisfactory anti-tank gun:

Calibre of projectile 3.5 inch. Weight of projectile 5 lbs. 8 oz. Weight of spigot and gas check 1 lb. 7 oz.

Total 6 lbs. 15 oz.

Weight of shot including casing and gas check 6 lbs. 15 oz. Size of shot No. 8. Material of easing Sheet metal or plastics. Thickness of casing .0l0-.0l5 inch. Weight of charge 29 grams. Material of charge Neoflak. Material of tie Brass. Minimum cross section of tie 0.2 sq. ins. Gas pressure to break tie 1.6 tons/sq. in. approx. Maximum gas pressure attained 3.5 tons/sq. in. approx. Length of round 2ft. 9 /2 ins. Length of front barrel 5 ft. 9ins. Length of rear barrel 6 ft. 2 ins. Radius of curvature of rear barrel 2 ft. 6 ins. approx. Angle of bend of rear barrel 538 Total length of gun 11 ft. 9ins.

Total weight of gun without round lbs. Total weight of round 13 lbs. 10 oz. Muzzle velocity of projectile 1,0001,200 ft./ sec. Muzzle energy of projectile 86,000 ft. lbs. approx. Range at 15 tangent elevation of front barrel 4,000 yards approx. Muzzle velocity of shot 1,000 ft./sec. approx. Range at which shot lands 300 yards approx.

The precise angle between the directions of discharge from the two barrels is not critical. An obtuse angle in the range to 140 is convenient, but angles nearer or nearer 90 are both possible.

It is essential for the bore of the rear barrel to be substantially uniform throughout its entire length. It is convenient, but not essential, for this bore to be the same size as the bore of the front barrel.

It is theoretically possible to have a rifled front barrel, and a rifled projectile, but this is not usually desirable because a rifled projectile would require a higher muzzle velocity, hence a larger propellant charge, hence a heavier round, a stronger and therefore heavier gun, and more conspicuous flash.

Although this invention is primarily concerned with anti-tank weapons, the same gun may be used to fire other projectiles for other purposes, for example anti-personnel projectiles.

Although the gun shown in the drawings is single-shot with hand loading, the invention may be embodied in guns with magazine loading and automatic firing.

I claim:

1. A portable infantry gun, comprising: a first tubular member defining an elongate, open-ended passage having a straight axis and forming chamber and front barrel portions of the gun; a second tubular member defining an elongate, open-ended rear barrel passage for the gun and having a curvilinear axis the two extremities of which are inclined to one another at an obtuse angle of the order of 150 to 140, the rear barrel passage having the same substantially uniform bore along its entire length; and means so detachably engaging the chamber portion of the first tubular member with the second tubular member as to join the passages with their axes in alignment at the joint and form a continuous open-ended tube within the gun; and a unitary round loaded within the chamber portion of the gun, the round comprising a projectile of large mass relative to the mass of the gun; a cup-shaped gas check on the rear end of the projectile adapted to seal the front barrel portion; a thin-walled casing containing a quantity of small shot and adapted to pass along the curved rear barrel passage; a second cup-shaped gas check on the forward end of the casing adapted to seal the rear barrel passage; a propellant charge enclosed between the two gas checks, adapted when fired to propel the projectile from the front barrel portion with low muzzle velocity of the order of 1000 to 1200 feet per second and to propel the casing and shot from the rear barrel passage, whereby, if the gun is adjacent the ground and the first tubular member is substantially horizontal, the projectile travels in a nearly flat forward trajectory to each a target with substantial energy, and the small shot travels in a curved trajectory obliquely upwards and then downwards to reach the ground with a non-lethal velocity, and the firing is accompanied by only very low emission of flash from the front barrel and rear barrel; and means carried by the chamber portion for firing the propellant charge.

2. For use with a unitary round of the type comprising a projectile of large mass relative to the mass of the gun, a cup-shaped gas check on the rear end of the projectile, a thin-walled casing containing a quantity of small shot and adapted to pass rearwardly relative to the projectile, a second cup-shaped gas check on the forward end of the casing, and a propellant charge enclosed between the two gas checks, adapted when fired to propel the projectile with low muzzle velocity of the order of 1000 to 1200 feet per second and to propel the casing and shot rearwardly, a portable infantry gun, comprising: a first tubular member defining an elongate, open-ended passage having a straight axis and forming chamber and front barrel portions of the gun; a second subular member defining an elongate, open-ended rear barrel passage for the gun and having a curvilinear axis the two extremities of which are inclined to one another at an obtuse angle of the order of 150 to the rear barrel passage having the same substantially uniform bore along its entire length; and means so detachably engaging the chamber portion of the first tubular member with the second tubular member as to join the passages with their axes in alignment at the joint and form a continuous open-ended tube within the gun; and means carried by the chamber portion for firing the propellant charge of a projectile, whereby, if the gun is adjacent the ground and the first tubular member is substantially horizontal, the projectile travels in a nearly flat forward trajectory to reach a target with substantial energy, and the small shot travels in a curved trajectory obliquely upwards and then downwards to reach the ground with a non-lethal velocity, and the firing is accompanied by only very low emission of flash from the front barrel and rear barrel.

References Cited in the file of this patent UNITED STATES PATENTS 1,108,717 Davis Aug. 25, 1914 1,280,579 Stone et al. Oct. 1, 1918 1,394,490 Giles Oct. 18, 1921 2,466,714 Kroger et al Apr. 12, 1949 2,657,630 Blacker Nov. 3, 1953 FOREIGN PATENTS 590,268 Great Britain July 14, 1947

Claims (1)

1. A PORTABLE INFANTRY GUN, COMPRISING: A FIRST TUBULAR MEMBER DEFINING AN ELONGATE, OPEN-ENDED PASSAGE HAVING A STRAIGHT AXIS AND FORMING CHAMBER AND FRONT BARREL PORTIONS OF THE GUN; A SECOND TUBULAR MEMBER DEFINING AN ELONGATE, OPEN-ENDED REAR BARREL PASSAGE FOR THE GUN AND HAVING A CURVILINEAR AXIS THE TWO EXTREMITIES OF WHICH ARE INCLINED TO ONE ANOTHER AT AN OBTUSE ANGLE OF THE ORDER OF 150* TO 140*, THE REAR BARREL PASSAGE HAVING THE SAME SUBSTANTIALLY UNIFORM BORE ALONG ITS ENTIRE LENGTH; AND MEANS SO DETACHABLY ENGAGING THE CHAMBER PORTION OF THE FIRST TUBULAR MEMBER WITH THE SECOND TUBULAR MEMBER AS TO JOIN THE PASSAGES WITH THEIR AXES IN ALIGNMENT AT THE JOINT AND FORM A CONTINUOUS OPEN-ENDED TUBE WITHIN THE GUN; AND A UNITARY ROUND LOADED WITHIN THE CHAMBER PORTION OF THE GUN, THE ROUND COMPRISING A PROJECTILE OF LARGE MASS RELATIVE TO THE MASS OF THE GUN; A CUP-SHAPED GAS CHECK ON THE REAR END OF THE PROJECTILE ADAPTED TO SEAL THE FRONT BARREL PORTION; A THIN-WALLED CASING CONTAINING A QUANTITY OF SMALL SHOT AND ADAPTED TO PASS ALONG THE CURVED REAR BARREL PASSAGE; A SECOND CUP-SHAPED GAS CHECK ON THE FORWARD END OF THE CASING ADAPTED TO SEAL THE REAR BARREL PASSAGE; A PROPELLANT CHARGE ENCLOSED BETWEEN THE TWO GAS CHECKS, ADAPTED WHEN FIRED TO PROPEL THE PROJECTILE FROM THE FRONT BARREL PORTION WITH LOW MUZZLE VELOCITY OF THE ORDER OF 1000 TO 1200 FEET PER SECOND AND TO PROPEL THE CASING AND SHOT FROM THE REAR BARREL PASSAGE, WHEREBY, IF THE GUN IS ADJACENT THE GROUND AND THE FIRST TUBULAR MEMBER IS SUBSTANTIALLY HORIZONTAL, THE PROJECTILE TRAVELS IN A NEARLY FLAT FORWARD TRAJECTORY TO EACH A TARGET WITH SUBSTANTIAL ENERGY, AND THE SMALL SHOT TRAVELS IN A CURVED TRAJECTORY OBLIQUELY UPWARDS AND THEN DOWNWARDS TO REACH THE GROUND WITH A NON-LETHAL VELOCITY, AND THE FIRING IS ACCOMPANIED BY ONLY VERY LOW EMISSION OF FLASH FROM THE FRONT BARREL AND REAR BARREL; AND MEANS CARRIED BY THE CHAMBER PORTION FOR FIRING THE PROPELLANT CHARGE.

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