PROJECTILES FOR FIRING FROM A CARTRIDGE This invention relates to projectiles to be fired from a gun, which carry a non-explosive charge of liquid or powdered material, and which are designed to rupture on impact with a target thus dispersing said charge over the area of impact. 5 Such projectiles may be used for delivering marker dyes or irritants to a target. In this way an individual person or animal may be marked for subsequent identification, or an individual person may be temporarily incapacitated by an irritant. UK Patents Nos 1,260,105 and 1,382,860 describe such projectiles in the form of a hollow teardrop-shaped envelope .10 containing a material for dispersion, provided with canted fins to stabilise the projectile by spinning in flight, and with a frangible body which disentegrates on impact to disperse the contents. UK Patent No 1,354,307 describes an alternative arrangement of projectile taking the form of a heavy metal body containing a frangible capsule which is shattered on 15 impact by a firing-pin type arrangement. Both types of projectile suffer from the difficulty of combining high strength under the high pressures and temperatures of firing with ease of dispersion, good aerodyniics and low risk of injury from a heavy projectile. According to the invention, a projectile for dispersing a liquid or * O powder charge over a target comprises a body, and a nose- compartment for containing said charge bounded by frangible side walls, said body being arranged to bear on said frangible side walls so as to apply, on impact with the target, an impulse to said side walls sufficient to cause them to rupture and to project said charge laterally to the line of flight of the 25 projectile. Preferably the body is also arranged so that the centre of gravity of the projectile is at a position slightly forward of its centre point to give the projectile the maximum directional stability in flight. The projectile may be fitted with a driving band and fired down a rifled 30 barrel for extra stability in flight. The projectile of the invention shows a considerable improvement in accuracy over finned projectiles. In addition, the body can be made relatively robust, and hence there is no danger of damage to frangible fins on the projectile. A particultr advantage of the invention is that bursting 35 of the frangible side walls improves the sideways scattering of material from the projectile, so that if a projectile according to the invention should hit the chest of a human target the agent will be effectively dispersed into his face. The body of the projectile may be solid or hollow and should 5 preferably be made of low density materials, such as plastics materials, so as to both maximise range and reduce the risk of injury on impact. The body should also be strong enough to resist high temperatures and pressures as the propellant charge burns, without distortion or melting. The body must, however, be sufficiently massive to impart sufficient *10 impulse 'to the frangible side walls of the nose compartment, on impact with a target, to rupture the side walls end project the charge contained therein sideways. The body may therefore be made in a number of ways. In a preferred embodiment the body is cylindrical and unitary in construction, made of 5 some relatively dense plastics material, preferably moulded rigid polyurethane, with a fitting at the forward end for the nose compartment, and shaped so as to apply stress preferentially onto the side walls of the nose compartment on impact with a target. Alternatively, especially when the body comprises a relatively light member, made for example of a rigid 20 foamed plastics material, preferably expanded polystyrene, the body member may have a weighted member attached to its forward end. Such a weighted member should be mounted behind the nose compartment so as to impart an impulse to the frangible side walls of the nose compartment. Conveniently the weighted member may be mounted immediately -25 behind the nose compartment, at the front of the body, so as to form the rear wall of the nose compartment, and may bear on the frangible side walls at its perimeter. In this case the weighted member may con9.ently take the form of a weighted angular washer or a cupped disk fitting over a. projecting portion of the light member, or a flat disk. The weighted member may be 30 made of a single material for example metal, but is preferably made of a plastics material with a suitably shaped piece of dense material either enclosed or embedded therein. In a preferred form the weighted member is made of polyethylene, and encloses a piece of heavy rubber. The diameter of the weighted member may be slightly greater than that of the remainder 3 of the projectile, so that the weighted member projects a small distance and may conveniently function as a driving band. The nose compartment may be made as a separate unit, to be filled and attached to the front end of a unitary body, or immediately in front 5 of the weighted member when present. Preferably the nose compartment is in the form of an essentially cylindrical cup or tube of a frangible material, with a fitting at its rear end, for example a plug and socket arrangement, to enable it to be attached to the body. The open front end of the cup or tube is closed with a nose plug, suitably aerodynamically *10 shaped and adapted at its rear and to be a push-fit into the open end of the cup or tube and thereby seal it, which may conveniently be made of the same material as a unitary body or the light member of a two-part body. Alternatively the nose compartment may be in the form of a nose cap , -' adapted to fit tightly around a suitable projecting portion at the front .15 of the body and constructed entirely of frangible materials. Suitable frangible materials for constructing the nose compartment should not form dangerous fragments on disintegration, and include plastics materials, a preferred plastics material being expanded polystyrene or foamed rigid - polyurethane. O_ It will be appreciated that if such a projectile is fired from a gun, the high acceleration stresses generated may cause the frangible side * walls of the nose compartment to rupture. This is especially likely if the nose compartment is in the form of the preferred embodiment described , above, i.e. a nose cup or tube closed with a nose plug, as the intertia of '25 the nose plug will increase such stresses. In these cases it is desirable to support the frangible side walls of the nose compartment with a protective sabot which is retained around the side walls while the projectile is accelerated down the barrel, but which is discarded in flight. A sabot of this type may conveniently be made in the form of 2 or more 30 segments of a cylinder which fit around the frangible side walls. These segments can conveniently be made of plastics material, such as polyethylene, and can be arranged to be held in place by utilising the natural elasticity of the material, if the segments as originally made have a radius of curvature of their inner face slightly less than the radius of the perimeter 4 of the frangible side walls. If the projectile is spin-stablised, then the segments of the sabot may be jettisoned by centrifugal force as the projectile leaves the gun barrel. The material to be dispersed into the atmosphere may be in the form 5 of a powder or a liquid, which may be a single component or a solution. In the case of a liquid, adequate sealing will be necessary around the edges of the walls of the nose compartment. Any liquids or solvents used should be compatible with the materials of the walls. Typical materials which may be dispersed in this way include marker dyes and incapacitating .l0 and lachrymatory agents. The projectile may be propelled by any suitable means, but is most * conveniently fired out of a gun by a propellant charge. If the body of the projectile is of unitary construction and made of a resilient plastics material such as a rigid polyurethane, then the rear end of the body may ,5 be moulded into an integral obturator/propellant capsule. If however the body has a rear light member made of light foamed or expanded plastics materials, it may be unable to resist the high pressures and temperatures generated on combustion of the propellant charge, and will normally require a separate obturator/propellant capsule, which prevents .damage to the projectile on firing and may be made of polyethylene, PVC or other suitable resilient plastics material. The projectile and obturator (if necessary) .* may be supplied together contained in a cartridge case, which may preferably be made of a light metal especially aluminium, or alternatively of cardboard or plastics materials. The walls of the cartridge case should continue beyond the nose of the projectile, to avoid damage to the frangible nose if the round should be dropped inadvertently, and the forward end of the cartridge case should not be crimped in any way, to avoid any likelyhood of premature rupture of the frangible walls on firing, but may be sealed by a light closure made for instance of plastics material, to be removed before 30 insertion into a gun barrel. The invention will now be described by way of example with reference to the following diagrams, in which, Fig 1 shows a cross section through a projectile of the invention with a nose compartment in the form of a cup and nose plug, fitted with a protective sabot.
Fig 2 shows an orthographic view of the projectile of Fig 1. Fig 3 shows a cross section through a projectile of the invention using a cupped disk as a weighted member with a completely frangible nose cap. 5 Fig 4 shows a cross section of the front section of a modified form of the projectile of Fig 3 using a heavy washer as a weighted member and a completely frangible nose cap. Fig 5 shows a cross section of the front section of a further modification of the projectile. 10 With reference to Figs. 1 and 2, a projectile comprises a cylindrical body 1, moulded of rigid polyurethane. The rear end of the body 1 is moulded to form an obturating rim 2, and a cavity to contain a propellant charge 3. In front of the body 1 i: fitted a nose compartment 4 in the form of a cylindrical cup moulded of frangible expanded polystyrene, which .15 is attached firmly to the body 1 by means of a projecting portion 5 at its rear and which co-operates with a socket 6 moulded in the forward end of the body 1. Otherx methods of attaching the nose compartment to the body will of course be apparent. The nose compartment 4 contains a powdered material 7 for dispersal at a target, and this may comprise a marker dye, an irritant aO or any other material. The open front end of the nose compartment is closed with a nose plug 8 * made of rigid polyurethane, the rear end of which is moulded to be on a tight push fit into the nose compartment 4, and the front end of which is aerodynamically shaped. 45 The frangible side walls of the nose compartment are surrounded by a cylindrical polyethylene sabot 9 which is made in two segments, of slightly smaller interior radius of curvature than the outside radius of the nose compartment 4 so as to be retained in place around the side walls of the nose compartment 4 during storage, but capable of being jettisoned by 30 centrifugal force as the projectile is fired and spin stabilised. The sabot 9 is of slightly greater length than the nose compartment 4, and is arranged to fit into shoulders 10 and 11 in the body 1 and nose plug 8 respectively, so that under the acceleration stresses generated on firing, the body 1 and nose plug 8 bears on the sabot 9 rather than on the frangible 6 side walls of the nose compartment 4, and thereby the said side walls are protected. The shoulders 10 and 11 are of depth such that the sabot lies flush with the perimeter of the body 1. The relative dimensions and weights of the body 1, nose plug 8, nose 5 compartment 4 and its contents 7 are arranged so that the projectile has the maximum aerodynamic stability in flight. On firing the projectile of Fig 1 down a rifled gun barrel, the frangible side walls of the nose compartment 4 are protected during acceleration down the barrel by the sabot 9, and the whole projectile is .10 spun by-engagement with the rifling. On leaving the barrel, centrifugal forces cause the two segments of the sabot 9 to fly off. On impact with a target, the momentum of the body 1 bears on the frangible side walls of the nose compartment 4 and causes them to rupture. The contents 7 of the nose compartment are thereby compressed and projected out sideways from the :15 projectile. The projectile is mounted inside a conventional cartridge case 12 made of aluminium, containing a primer 13. A light polyethylene closure 14 retains the projectile during storage and also prevents ingress of moisture. * With reference to Fig 3, a projectile has a body made in two parts, a ,0 light member and a weighted member. The light member 21 is cylindrical and made of expanded polystyrene, at the forward end of which there is a * cylindrical projecting portion22 of reduced diameter. Over this projecting portion fits a weighted member, which comprises a dished polyethylene cap 23 which is a tight push-fit over the projecting portion 22 and contains a .25 shaped piece of heavy rubber 24. The rim 25 of the cap 23 should not project beyond the perimeter of the body 21 so that the projectile is not spun apart if the rim 25 engages with rifling on firing. The entire body should be of such a diameter that it will engage with the rifling of the weapon it is to be fired from. A nose compartment is formed by a frangible 30 expanded polystyrene nose cap 26, which is a tight push--fit over the forward part of the weighted polyethylene cap 23. The nose compartment contains a quantity of a powdered material 27 for dispersal at a target, and may comprise a marker dye, an irritant or any other material. The position of the weighted cap 23 is such that the projectile balances so that the maximum directional stability is imparted to it in flight. The projectile is mounted inside a conventional aluminium cartridge case 12, fitted with a primer 13 and closed with a light polythene closure 14 as above. As the body is made of light expanded polystyrene it is necessary to provide a 5 separate obturator/propellant capsule 27 made of polyethylene, and containing a propellant charge 28. With reference to Fig 4, the cap 23 and rubber 24 of Fig 3 are replaced by a metal washer 31 which fits tightly around the projecting portion 22. The rear end of the frangible expanded polystyrene cap 26 in .0 this case fits tightly over the projecting portion 22, to form a nose . compartment containing a material 7 to be dispersed on impact. * With reference to Fig 5, the nose cap 26 of Fig 3 is replaced by a hollow tube4l of frangible expanded polystyrene which is a tight fit over the polyethylene cap 23 and which is sealed at its front end by a tight }6,5 polyethylene closure 42 which is a tight push fit in the tube 41. This nose compartment contains a material 7 to be dispersed on impact. Both the projectiles of Figs 4 and 5 may be mounted inside a cartrige case as described above, with a separate obturator/propellant capsule and fired from a gun down a rifled barrel. On firing the projected of Figs 3, 4 and 5 above from a gun, the light nose compartments 26, 41, 42 do not generate sufficient stress on *0 acceleration to fracture the frangible side walls. On impact with a target the weighted members 23, 31 bear on the frangible side walls of the nose cap 26, 41 causing them to rupture. The contents 7 of the nose compartment are thus immediately dispersed in a sideways direction from the projectile. e