Patent Application
20150144019
The present invention relates to a lead-free ammunition with improved performance, especially intended for small-bore weapons of the firearm and machine gun type.
One problem with modern-day conventional ammunition, also referred to as conventional cartridge ammunition, is the presence of toxic heavy metals, especially lead, which is found in the projectile, propellant powder and priming system of the cartridge. The use of conventional ammunition in training and conflict areas means considerable loads on the environment, with subsequent risks for animals and humans. Large-scale use additionally means costly clean-ups for the restoration of the environment. In the USA it is calculated that the American army uses 300 to 400 million lead-containing cartridges per annum, the majority of which are used in practice firings on practice ranges close to military bases.
The cost of cleaning up contaminated training areas is calculated at nine billion dollars. The cost of cleaning up contaminated training and conflict areas in other parts of the world is thought to be even higher.
A further problem with said conventional ammunition is the toxic gases and particles/dust which are formed in the combustion of the priming composition and propellant powder of the ammunition. Furthermore, environmentally hazardous metal particles, above all lead particles from the lead core of the projectile, but also zinc and copper particles from the tombac jacket of the projectile are generated by the friction which arises between the projectile and the rifled inner side of the weapon barrel upon firing of the projectile.
Minor quantities of lead and copper dust are also formed when the projectile hits a target.
Discharge of toxic particles and gases poses a risk not only for the marksman but also for humans in the surroundings.
There is therefore a need for ammunition in which environmentally hazardous heavy metals in the projectile, the propellant powder and the priming system are replaced with other materials, or in which the proportion of environmentally hazardous metals has been reduced to a level which is as low as possible and which is acceptable.
In the light of the above, a new generation of projectiles has recently been developed, in which lead has been replaced with other materials. In patent specification US 20060107863 is described a projectile in which the core of the projectile is made up of a compacted metal powder comprising a mixture, or mixtures, of iron powder, copper powder and tin powder. In patent specification US 2008 0000 379 is described a projectile whose core is made up of a composite material comprising a mixture of compacted metal and mineral powder.
One problem with these composite-based projectiles is, however, their low penetrability. The, generally speaking, lower strength of the composite material compared with solid metals means that composite projectiles are more easily splintered when they hit their target, compared with lead projectiles.
In order to improve the penetrability and, at the same time, address the environmental problem, projectiles having solid steel cores have been developed. In patent specification US6973879 is described a lead-free projectile in which the core consists of a hardened steel.
The projectile lacks a conventional jacket, and has therefore been replaced with a surface coating constituted by a soft metal, copper, nickel, zinc, aluminum or mixtures thereof, plated directly onto the steel core.
One problem with said steel projectile is the environmentally hazardous metal particles and metal dust which are generated by the friction which arises between the projectile and the inner side of the weapon when the projectile is fired from the weapon. The friction adversely affects the performance of the projectile, at the same time as discharge of harmful metal particles, primarily copper, nickel and zinc, is at risk of exceeding permitted limit values, for example 2 mg/m3 for respirable copper dust.
A further problem is the toxic substances which are formed in the combustion of the priming and propellant compositions of the ammunition.
Another problem is difficulties in adapting the projectile to the different demands which are made with respect to performance and the environment for different weapon applications.
A principal object of the present invention is an improved lead-free projectile for small-bore weapons, configured such that the friction between the projectile and the barrel of the weapon upon firing of the projectile is reduced such that the proportion of environmentally hazardous gases and metal particles is reduced, at the same time as the performance of the projectile is maintained or improved.
A further object of the present invention is a lead-free cartridge for small-bore weapons, configured such that, when a projectile is fired from the weapon, the quantity of toxic substances in the combustion gases from the priming and propellant compositions of the cartridge is reduced, at the same time as the performance of the weapon is maintained or improved.
Another object of the present invention is a method for, when a projectile is fired from a small-bore weapon, reducing the wear between the projectile and the barrel of the weapon so that the quantity of environmentally hazardous gases and metal particles is reduced, at the same time as the performance of the projectile is maintained or improved.
Yet another object of the present invention is a projectile configuration which can easily be adapted to different performance and environmental demands in different weapon applications.
Said objects, and other aims which have not been enumerated here, are satisfactorily met by that which is stated in the present independent patent claims. Embodiments of the invention are defined in the dependent patent claims.
Thus, according to the present invention, a lead-free projectile, having the length Ltot, for small-bore weapons has been provided, comprising a hard-metal core, wholly or partially enclosed by a metal jacket, wherein the projectile is configured for a lower friction between the projectile and the weapon upon firing of the projectile, so that the quantity of metal particles and environmentally hazardous gases from the projectile is reduced, at the same time as the performance of the projectile is maintained or improved, wherein the core of the projectile comprises a front core part, constituting the penetrator part of the projectile, and a rear core part, constituting the ballast part of the projectile.
The projectile is characterized
According to further aspects of the lead-free projectile, it is the case according to the invention:
that the rear core part comprises at least 90% unhardened steel,
that the jacket comprises at least 90% steel plated with a thin layer of copper,
that the jacket is divided into a front jacket part, an intermediate jacket part and a rear jacket part, wherein the thickness of the intermediate jacket part is at least twice as thick as the thickness of the front jacket part and the rear jacket part, and that the three jacket parts constitute three separate components joined together with one another on the core of the projectile by shrinkage or threading,
that the intermediate jacket part is surface-treated by sulfating in order to minimize the wear in the weapon,
that at least 30% of the rear core part is conical,
that the jacket comprises inner longitudinal rifling or grooves for preventing rotation of the front and rear core parts of the projectile inside the jacket,
that the jacket comprises outer longitudinal rifling or grooves for reducing the friction between the projectile and the weapon,
that the jacket comprises outer transverse rifling or grooves for reducing the friction between the projectile and the weapon.
According to the present invention, a lead-free cartridge for small-bore weapons, in which the proportion of toxic substances in the combustion gases from the priming and propellant compositions of the cartridge upon firing has been eliminated or heavily reduced, at the same time as the performance of the cartridge is maintained or improved, has also been provided.
The cartridge is characterized in that the cartridge comprises a lead-free propellant powder, a lead-free primer comprising a zinc-free priming composition, a lead-free case and a lead-free projectile.
According to the present invention, a method has been provided for reducing the wear between a projectile, comprising a hard-metal core wholly or partially enclosed by a metal jacket, and a weapon, wherein the quantity of environmentally hazardous gases and metal particles which are generated upon firing of the projectile from the weapon is reduced, at the same time as the performance of the projectile is maintained or improved, wherein the core of the projectile is configured with a front core part, constituting the penetrator part of the projectile, and a rear core part, constituting the ballast part of the projectile.
The method is characterized:
According to further aspects of the method, it is the case according to the invention:
that the thickness of the jacket is made thicker on that part of the projectile which is in contact with the inner side of the barrel of the weapon,
that the intermediate jacket part (12) is surface-treated by sulfating in order to minimize the wear in the weapon,
that at least 30% of the rear core part is configured as a truncated cone,
that the jacket is configured with inner longitudinal rifling or grooves for preventing rotation of the front and rear core parts of the projectile inside the jacket,
that the jacket is configured with outer longitudinal rifling or grooves for reducing the wear between the projectile and the barrel of the weapon, that the jacket is configured with outer transverse rifling or grooves for reducing the wear between the projectile and the barrel of the weapon.
The invention implies a number of advantages and effects, of which the most important are:
The replacement of environmentally hazardous heavy metals, such as lead, in all the various parts of the cartridge, with non-hazardous metals such as steel means that the adverse effect of the lead on the environment can be eliminated, which in turn eliminates the need for clean-up measures for restoration of the environment.
By configuring the projectile such that the friction between the projectile and the inner side of the barrel is reduced, at the same time as the air resistance of the projectile is reduced, the quantity of environmentally hazardous metal particles and dust from the projectile can be reduced, whilst, at the same time, the ballistics and performance of the projectile are improved.
The fact that the priming and propellant compositions of the cartridge are configured such that the proportion of toxic substances in the combustion gases from the weapon is eliminated or reduced means that the risks for the marksman and for humans in the surroundings can be heavily reduced.
The modular structure of the projectile having a two-part core with mutual freedom of rotation between the cores enables simple and rapid adaptation, fitting/exchange, of the front core with regard to different environmental and performance demands which can conceivably be placed on the projectile for different applications.
For example, a projectile configuration can be chosen in which the front core part/the penetrator is made of hardened steel or tungsten carbide and the rear core part/the ballast is made of cheaper unhardened steel.
The modular structure of the projectile with three-part jacket enables simple and rapid fitting by shrinkage or threading of the different jacket parts, with regard to the demands which are placed on the jacket.
For example, a jacket configuration can be chosen in which the intermediate part of the jacket is constituted by a softer metal, whilst the front and the rear jacket part are made of a harder metal.
Said modifications of the cartridge and of the projectile result in increased safety for the marksman and for persons in the vicinity. For example, the safety distance to the weapon can be reduced, as can the ventilation requirements in shooting galleries, which implies environmental advantages and cost savings.
Further advantages and effects of the invention will emerge from a study and consideration of the following, detailed description of the invention, with simultaneous reference to the drawing figures, in which:
a shows schematically a longitudinal section of a projectile comprising a projectile core and a jacket.
b shows schematically a special embodiment of the cylindrical part of the projectile core in
As stated earlier, an overall aim of the present invention is to eliminate or heavily reduce the proportion of environmentally hazardous heavy metals in the various parts of a cartridge and to reduce the proportion of toxic substances, gaseous as well as particulate, which are formed in the combustion of the priming and propellant compositions of the cartridge, at the same time as the performance of the cartridge is maintained or improved.
Historically, the emphasis on product development for small-bore ammunition has primarily been focused on improving the performance of the ammunition. Only more recently have we begun to study the impact of the ammunition on the environment.
Totally lead-free, civil or military small-bore ammunition represents a relatively small niche in the current market, yet the market is growing rapidly. Historically, heavy metals such as mercury and lead, above all lead, have been and are still today the most common type of material found in cartridge constructions.
It is not fully clear how a lead-free cartridge acts in a ballistic respect, in terms of the weapon, the trajectory or the target.
At present, there is only one 5.56×45 mm lead-free cartridge which is NATO-qualified, namely: NAMMO's 5.56×45 mm Ball Non Toxic 4 High Performance (NATO design AC/225-128A).
In order to manage to reproducibly produce a new lead-free cartridge with fully encased steel core, having new lead-free components in the priming chain, in the priming cartridge, in the propellant powder, and in the projectile, so that the discharges of toxic heavy metals are eliminated or lowered, at the same time as the performance of the cartridge is maintained or improved, it is not sufficient to change only the material, but rather changes to the design of the projectile are also required.
The choice of powder type and priming composition 6 has been made with a view to, on the one hand, minimizing the proportion of toxic substances in the combustion gases and, on the other hand, matching the ballistic properties of the projectile. The cartridge case 4 is of standard type, free from environmentally hazardous heavy metals. Experimental tests show that said propellant powder means a reduction of the ammonia proportion in the combustion gases by more than 50%, of the hydrogen cyanide proportion by about 75%, and of the copper proportion by about 40%, compared with a conventional propellant powder. Experimental tests also show that said priming composition means a reduction of the zinc proportion in the combustion gases by about 50%, compared with a priming composition containing zinc peroxide.
In
The modular structure of the core 6 means that different core parts can easily be combined in dependence on the target type. For example, the front core part 7 can comprise tungsten carbide for target types in which high demands are placed on the penetrability of the projectile 5. The modular structure also means that the center of gravity (TP) of the projectile 5 can easily be adjusted by combining different core parts with different configuration, length, width, etc., which means easier optimization of the ballistics of the projectile during its trajectory. The joining together of the core parts 7, 8 is effected via a coupling which achieves radial guidance and mutual freedom of rotation.
The two core parts 7, 8 are configured to minimize the contact surface between the projectile 5 and the inner side of the weapon in order thus to reduce the quantity of metal particles which is torn away from the projectile 5 in connection with the projectile 5 being fired from a barrel.
At the same time, the rear core part 8 is configured to reduce the air resistance of the projectile 5 and thus improve the external ballistics of the projectile 5. The front core part 7 is configured as an oblong cone 5, which accounts for approximately half the total length Ltot of the projectile 5. The rear core part 8 comprises, on the one hand, a cylindrical part and, on the other hand, a conical part having the cone angle α. The length Lk of the conical core part amounts to maximally 0.24×LTOT and the cone angle α shall lie within the range 5-9°. Tests have shown that the cone angle α of the projectile is optimally, given lowest possible air resistance, 6°+/−0.1°.
The cylindrical portion of the rear core part 8 is weakly conical, with a cone angle α within the range 0°<α<1°, preferably 0.55°. The reason is that the conical shape reduces the obtuse angle between the core and the jacket 10, thereby reducing the friction forces between the projectile 5 and the barrel of the weapon.
A short cylindrical portion achieves, however, a strong reduction of the inner friction surface between the rear core part 8 and the jacket 10, which poses a problem, since the core 6 can then acquire a different rotational velocity from the jacket 10, causing the projectile 5 to become unstable. In order to prevent different rotational velocities and thus the risk of instability, the core 6, in a special embodiment in
The grooves 14 also imply an advantage from the production viewpoint, since the grooves 14 act as a tool in the fitting of the core 6 and jacket 10.
The external ballistics/flying ability of the projectile 5 is determined in large part by the center of gravity T of the projectile 5. For a 5.56 caliber projectile 5, the distance (LTP) between the tip of the projectile 5 and the center of gravity TP of the projectile shall ideally lie within the range:
0.55Ltot≦LTP≦0.60Ltot.
Furthermore, the length LC of the cylindrical part of the rear core part 8 shall be as short as possible and lie within the range
0.25Ltot≦LC≦0.31Ltot.
The front core part 7, i.e. the penetrator, is preferably produced from a hardened steel having a hardness of at least 500 Hv3. Other materials too, such as tungsten carbide, can advantageously be used. The rear core part 8 is preferably produced from a steel having a maximum hardness of 160 Hv3. The jacket 10 of the projectile is preferably produced from a standard copper-based material, also referred to as tombac. Preferably, the tombac jacket 10 comprises a mixture of 90% copper and 10% zinc. In an alternative embodiment, the jacket comprises at least 90% steel plated with a thin layer of copper. The jacket 10 is produced, preferably, by a standardized method, for example by cold pressing and upsetting.
In order to minimize the discharge of metals to the environment, the thickness of the jacket 10 is greatest on the cylindrical part of the jacket 10, that is to say on that part of the jacket 10 which is in contact with the inner side of the barrel upon firing of the projectile 5.
The thickness of the jacket 10 is expediently optimized by being made thicker on the cylindrical part of the jacket where the wear against the barrel occurs, preferably twice as thick as the other parts of the jacket 10.
In a special embodiment, the jacket 10 is divided into a front jacket part 11, an intermediate jacket part 12 and a rear jacket part 13, wherein the intermediate jacket part 12 is at least twice as thick as the front and the rear jacket part 12, 13. The three jacket parts are here constituted by three separate components, which can be joined together on the core of the projectile 5, for example by shrinkage, welding or threading. The advantage with a modularly constructed jacket 10, as with a modularly constructed core 6, is that the jacket 10 can easily be configured with regard to different ballistic and environmental demands which can be placed on the projectile 5. For example, the intermediate jacket part 12 can be made of a tombac material, whilst the front jacket part 11 and the rear jacket part 13 are made of a non-metallic material, for example a composite material. Furthermore, the different jacket parts 11, 12, 13 can be surface-treated in different ways. For example, the intermediate jacket part 12 can be surface-treated, in order to minimize the wear in the barrel, by sulfating or tinning, for example, whilst the front jacket part 11 and the rear jacket part 13 are surface-treated for the sole purpose of minimizing the air resistance of the projectile 5 during its trajectory.
In a further special embodiment of the jacket 10, the jacket 10 comprises inner longitudinal rifling or grooves (not shown) for preventing rotation of the core 6 of the projectile 5 inside the jacket 10, compare with the earlier described special embodiment of the cylindrical part of the core with grooves 14 or rifling producing the same effect.
In a further special embodiment of the jacket 10, the jacket 10 comprises outer longitudinal grooves or rifling (not shown) for reducing the wear between the projectile 5 and the barrel of the weapon.
In another special embodiment of the jacket 10, the jacket 10 comprises outer transverse grooves or rifling (not shown) for reducing the wear between the projectile 5 and the barrel of the weapon.
The configuration of the projectile with extended and optimized rear core part and smaller contact surface, in combination with the higher strength of the projectile, has been shown in tests to reduce the proportion of metal particles from the projectile by 10-20%, at the same time as the ballistic properties of the projectile have been improved. For example, the decrease in velocity of the projectile during its trajectory has been reduced, at the same time as the penetration in plate shooting is very good up to at least 725 m.
The described configuration means that the projectile, in tests according to NATO standard, can penetrate a steel plate of 3.5 mm thickness (SAE 1010/1020 having a hardness of 99-124 HB) at a distance of at least 725 m, which is 27% better than is required according to NATO standard at a firing distance of 570 m.
The improved ammunition inclusive of projectile has been shown in tests to meet internal, external and terminal ballistic requirements and other requirements according to NATO's STANAG 4172 and NATO Multi Manual Of Proof & Inspection PFP(NAAG-LG/1-SG/1)D(2004)1 for 5.56-caliber military ammunition.
This means that the ammunition meets the demands placed by NATO on precision, pressure level, temperature, ballistic trajectory consistency and safety when used in functional weapons.
The invention is not limited to the embodiments shown, but can be varied in different ways within the scope of the patent claims. It will be appreciated, inter alia, that the number, size, material choice and form of the materials included in the ammunition and the component which are of importance to the invention, for example propellant powder, priming composition, can be adapted with regard to one another and with regard to other included elements and components in the ammunition.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1200305-9 | May 2012 | SE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/SE2013/000077 | 5/16/2013 | WO | 00 |
