Ammunition and explosives – Cartridges – Practice projectile type
Reexamination Certificate
2000-04-06
2001-09-04
Jordan, Charles T. (Department: 3641)
Ammunition and explosives
Cartridges
Practice projectile type
C102S447000, C102S439000
Reexamination Certificate
active
06283035
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This application relates to reduced propellant ammunition cartridges, particularly subsonic cartridges for clandestine use of weapons which normally fire supersonic projectiles.
2. Description of the Prior Art
There is a requirement for subsonic cartridges for clandestine use of weapons which normally fire supersonic projectiles. These subsonic rounds need to work interchangeably with supersonic rounds in so far as they need to fit properly in the same firearm chamber. While it seems it should be an easy job to produce the subsonic rounds by simply reducing the propellant charge until the velocity is adequately reduced, it is known in the art this does not work for a number of reasons.
When the propellant charge becomes small in relation to the total volume within the cartridge case, ignition of the propellant changes with respect to the location of that propellant within the case. Thus, shooting upward with the propellant charge near the primer gives different velocity results than when shooting downward with the propellant charge forward. It is also known that some small charge weights can burn at a very high rate thereby producing chamber pressures above that of full velocity rounds that can cause the cartridge to explode in the weapon with catastrophic results.
Through the years, a number of solutions have been tried which include addition of inert and consumable filler materials as well as addition of expandable inner sleeves that occupy the empty space between the propellant and the projectile, e.g., see U.S. Pat. No. 4,157,684.
The inert and consumable filler materials create problems related with their mass, water retention, combustility and by-products of combustion. Further, they can suffer from inability to keep the propellant from migrating into them due to vibration and handling shocks whereby they have an effect on ignition of the propellant.
The use of expandable inner sleeves limit the production rate in automated loading equipment due to the time it takes the sleeves to expand following insertion and the need to check to assure the sleeve has expanded prior to loading the propellant.
The result of such prior attempts to solve the production of reliable subsonic cartridges has been subsonic rounds that have a larger spread in velocity and thus less accuracy potential than what is desired while associated production costs can be significantly more then full velocity rounds.
Other attempted solutions to the problems associated with the production of subsonic ammunition have been disclosed. For example, see U.S. Pat. No. 5,822,904 which teaches use of stepped down stages in the discharge end of cartridge casings and U.S. Pat. No. 5,770,815 which teaches use of reducing internal casing volume with molded foam fillers as alternative possible solutions.
The present invention provides an improved solution to the subsonic ammunition problems that makes it possible to manufacture better and more price competitive subsonic ammunition then has been possible heretofore.
OBJECTS
A principal object of the invention is the provision of improved forms of reduced propellant ammunition cartridges, particularly subsonic cartridges for clandestine use of weapons which normally fire supersonic projectiles.
Further objects include:
1. Improving the overall efficiency of subsonic ammunition by limiting the weight to just what is required for accelerating the projectile to the desired charge velocity.
2. Creating subsonic ammunition that has no more kinetic energy than just that required for accelerating the projectile.
3. Enabling the internal modification of standard cartridges for given weapons to be of minimum volume to handle only the propellant required to create the desired subsonic cartridge.
4. Lowering the manufacturing costs of creating subsonic ammunition.
5. Providing an improved method for manufacture of subsonic ammunition that is easily adapted to existing loading equipment.
6. Providing an improved method for manufacture of subsonic ammunition that can be adapted to a wide variety of cartridge case sizes and designs.
Other objects and further scope of applicability of the present invention will become apparent from the detailed descriptions given herein. It should be understood, however, that the detailed descriptions, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent from such descriptions.
SUMMARY OF THE INVENTION
The objects are accomplished in accordance with the invention by the provision of a simple and economical method of converting existing cartridge cases to hold less than the standard volume of propellant while eliminating the serious ignition and filler problems known to arise with prior art subsonic ammunition.
Basically, the invention depends upon the use of a length of pliable tubing that has an outside diameter just slightly smaller than the inside diameter of the casing neck portion that holds the cartridge projectile. The tubing is cut to a length that allows it to snugly fit between the base of the cartridge case and the casing neck portion.
Such a sized tube is inserted through the neck portion and then the distal end of the tube is manipulated so it expands below the neck portion and is thus held captive in the cartridge case. Such manipulation can advantageously be swaging of the distal end with a tool or by the rear end of the projectile that is installed in the cartridge.
The pliable tube is advantageously made of metal, particularly aluminum metal, but brass or other malleable metal may be used. Also, such tube may be made of plastic, particularly, plastic that can be deformed like metal by swagging or by use of a heated shaping tool.
The wall thickness of the pliable tube is chosen so the volume that is provided inside the tube below the base of the projectile and above the base of the casing is nearly equal to the required propellant charge need to achieve the desired velocity. In this way, the propellant charge is confined to a volume ideal to the requirements of the round. Thus, when the primer is struck by the firing pin, the propellant inside the tube is sufficiently contained by the pliable tube to assure proper propellant ignition continues while the tube is swollen or ruptured. This allows the propelling gases to fill the remaining internal volume of the cartridge case. The strength of the tube is such, however, that the propellant is properly ignited and burning before the tube swells or ruptures so the propellant continues burning in a normal manner with the net result being that proper projectile velocity is maintained to move the projectile down the firearm barrel at the proper velocity without having to expend any energy in propelling filler material down the barrel with it.
The efficiency of subsonic ammunition as provided by the invention is thus improved relative to prior known subsonic ammunition. Furthermore, the modification of the cartridge in accordance with the invention has only to deal with the minimum required amount of propellant gases. Also, since ammunition created in accordance with the invention does not need to include filler material, the firearm silencer is not effected by having to handle filler material both from an impact standpoint and from the possibility of being plugged up by filler.
REFERENCES:
patent: 228494 (1880-06-01), Valentine
patent: 788266 (1905-04-01), King et al.
patent: 4157684 (1979-06-01), Clausser
patent: 4682545 (1987-07-01), Jett, Jr.
patent: 4867065 (1989-09-01), Kaltmann et al.
patent: 5770815 (1998-06-01), Watson, Jr.
patent: 5822904 (1998-10-01), Beal
patent: 0049125-A1 (1982-04-01), None
Adkins Michael G.
Olson Douglas D.
Jordan Charles T.
Knight Armamant Company
Palmer Carroll F.
Semunegus Lulit
LandOfFree
Reduced propellant ammunition cartridges does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Reduced propellant ammunition cartridges, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reduced propellant ammunition cartridges will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2516350