The present invention relates to a non-lethal telescoping cartridge for deployment of non-lethal ordnance. In particular, a low impulse non-lethal telescoping cartridge is disclosed, having a payload cup containing non-lethal projectiles, telescopically mounted upon a cartridge case base which, when fired, telescopes out from the base and releases the non-lethal projectiles at a non-lethal velocity. The cartridge of the present invention may be fired from an automatic weapon, such as a 40 mm MK19 grenade machine gun.
Traditional non-lethal ordnance comprises cartridges that contain, for example, projectiles consisting of metal balls coated with a thin layer of plastic or rubber, fabric bags which are filled with lead shot (so-called “bean bags”), and “rubber bullets” formed of hard rubber, foam, plastic or wood. These traditional non-lethal projectiles have various problems, such as a short range, poor accuracy and possible lethality.
For example, non-lethal projectiles are generally aerodynamically unstable due to the shape needed for non-lethality (generally approximately round, such as rubber bullets, or amorphous, such as a bean-bag). As such, the aerodynamic forces exhibited by these projectiles tend to vary and be inconsistent, which leads to poor accuracy. In the case of a bean-bag projectile, the projectile tends to flatten out in flight, forming a flat high-drag flight surface. Furthermore, non-lethal projectiles are generally launched from smooth bored guns which, unlike rifled bores, do not impart spin to the projectile and, as a result, decrease accuracy.
To overcome the accuracy problems discussed above, spin-stabilized non-lethal projectiles have been proposed, such as disclosed in U.S. Pat. No. 6,041,712 to Lyon. However, various difficulties remain in the use of such devices. For example, when desiring to use non-lethal cartridges in automatic weapons such as the 40 mm MK19 grenade machine gun, the ammunition must produce sufficient blowback (i.e., energy transferred to the bolt) to recycle the weapon, and must accurately conform to the chamber dimensions of the weapon so as to avoid jamming of the weapon.
An automatic weapon such as the 40 mm MK 19 grenade machine gun is actuated by the direct blowback of the cartridge case against the bolt upon expansion of the propellant gas during the time between cartridge ignition and projectile exit from the barrel. The MK19 is designed to function when firing 40 mm cartridges with a cartridge impulse of approximately 13 to 15 pounds-seconds. Reduced cartridge impulses provided by lower mass projectiles (such as blanks, training cartridges and non-lethal cartridges) and/or reduced chamber pressure results in reduced energy transferred to the bolt. Consequently, the weapon cyclic rate, and potentially the ability of the cartridge to recycle the weapon at all, may be in question.
U.S. Pat. Nos. 6,178,889, 6,324,983 and 6,324,984 disclose a low impulse telescoping cartridge, a sub-caliber projectile for low impulse cartridges, and a payload mechanism for low impulse cartridges, respectively. The present invention differs from these disclosures in several respects.
For example, in the present invention, a step is provided on the cartridge case forward of the rim, to improve the interface with the MK19 bolt face and improve weapon functional reliability when firing low impulse telescoping cartridges. The present invention further provides a rifled payload cup for launching spin stabilized projectiles from smooth bore weapons and from rifled weapons where use of the weapon rifling is not desired or practical. In addition, an end cap is provided which snaps over the end of the payload cup or body to close the end of the payload cup and retain the payload within the payload cup until the moment of firing.
The present invention also provides a high/low adapter in the cartridge case which vents thru the side of the brass case containing the propellant charge, effectively using the brass case as a rupture membrane to assure that sufficient gas pressure is produced to provide consistent propellant burning. The high/low adapter in the cartridge also contains a forward vent hole and a pocket for retaining a firing pin for initiating the primer in the base of the high/low adapter in the payload cup.
One embodiment of the high/low adapter in the payload cup uses a pistol caliber brass case and pistol primer. A cover that attaches to the base of the pistol case serves as a retainer for the primer to ensure that the primer does not blow out of the brass case. Another embodiment of the high/low adapter in the payload cup uses a rifle caliber brass case.
A spring in the form of a hollow cylinder is used inside the cartridge to maintain the position of the payload cup relative to the cartridge case during chambering and firing. The spring is made of, for example, a polymer. The spring helps to ensure that the payload cup is against the forward stop at the moment of firing.
In contrast, the '983 patent, although disclosing a telescoping cartridge, utilizes a smoothbore sub-caliber payload cavity which is used with a sub-caliber rifled barrel insert when launching spin stabilized projectiles. The present invention provides for rifling the payload cavity for launching sub-caliber spin stabilized projectiles, thus eliminating the need to use a sub-caliber barrel insert.
The present invention improves upon the prior art through, among other features, the use of 1) a step on the case forward of the rim to improve the interface with the MK19 bolt face to improve the weapon functional reliability, 2) a rifled payload cup for launching spin stabilized projectiles, 3) an end cap that snaps over the end of the payload cup or body to close the end of the payload cup and retain the payload within the payload cup until the moment of firing, 4) a rear high/low adapter which has one or more holes thru the side thereof to allow venting directly thru the side of the brass case, eliminating the need for a separate rupture disk to control the propellant ignition, 5) provision of a firing pin and firing pin cavity in the forward end of the rear high/low adapter for initiating the forward high/low adapter in the payload cup, 6) a retaining cover for holding the primer in the base of the brass case in the forward high/low adapter in the payload cup, and 7) a spring used inside the cartridge case to maintain the position of the payload cup relative to the cartridge case during chambering and firing.
It is a first object of the present invention to provide a low impulse non-lethal cartridge for use in conventional automatic weapons, such as the 40 mm MK19 grenade machine gun.
It is a second object of the present invention to provide non-lethal ammunition capable of accelerating a bolt to the rear of the weapons chamber independently of the impulse generated from launching of the non-lethal projectile.
It is a third object of the present invention to provide a non-lethal cartridge for use in conventional automatic weapons, such as the MK19 grenade machine gun, which do not necessitate changes to the weapon itself in order to utilize the ammunition, but which also allow effective and accurate firing of the reduced velocity and/or reduced mass (non-lethal) projectiles.
It is a fourth object of the present invention to provide an ammunition configuration which allows for reliable loading and firing of the ammunition in conventional automatic weapons, such as the MK 19 grenade machine gun.
It is a fifth object of the present invention to provide an ammunition configuration having high/low propellant chambers which allow for consistent propellant burn, and which provide consistent interior ballistics, while avoiding lethal propellant projectile characteristics.
The invention will be better understood, and further objects, features, and advantages thereof will become more apparent from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings.