Title:
CASELESS AMMUNITION CARTRIDGE
United States Patent 3557700


Abstract:
A caseless ammunition cartridge comprised of a support tube carrying a prctile at one end and a primer cup at the other. A neck portion of the same material as the primer cup is secured at the top of the support tube and a plurality of explosive discs are provided around the support tube between the primer cup and the neck portion.



Inventors:
Quinlan, Joseph B. (Philadelphia County, PA)
Vetter, Elwood (Bucks County, PA)
Application Number:
04/799244
Publication Date:
01/26/1971
Filing Date:
02/14/1969
Assignee:
ARMY USA
Primary Class:
Other Classes:
102/288
International Classes:
F42B5/18; (IPC1-7): F42B5/18
Field of Search:
102/38,C
View Patent Images:
US Patent References:



Primary Examiner:
Stahl, Robert F.
Claims:
We claim

1. A caseless ammunition cartridge comprising in combination:

2. A caseless ammunition cartridge as defined in claim 1, wherein said ignition means includes a round primer cup fitting into the support tube to join therewith and having a flat base end containing a primer element.

3. A caseless ammunition cartridge as defined in claim 2, wherein said primer cup includes a shoulder arranged and constructed to provide a seat for the support tube and said stacked propellant discs.

4. A caseless ammunition cartridge as defined in claim 2, wherein the neck ring and the primer cup are of a single-base propellant, and wherein the support tube and the propellant discs are constructed of a double-base propellant in sheet form.

5. A caseless ammunition cartridge comprising in combination:

6. A caseless ammunition cartridge as defined in claim 5, wherein the material of the propellant discs and of the support tube is a compound of nitrocellulose and nitroglycerine, and wherein the material of the primer cup and of the neck ring is a mixture of nitrocellulose and a binder.

7. A caseless ammunition cartridge comprising in combination:

8. A caseless ammunition cartridge comprising in combination:

9. A caseless ammunition cartridge as defined in claim 6, wherein the support tube and primer cup base with the stack of disc charges and neck ring are joined in concentric relation to provide a body for said cartridge of unitary construction and uniform outside diameter to fit a firing chamber, and wherein the laminated support tube is open between the projectile and the primer base to provide a combustion space in rear of said projectile.

Description:
The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to use of any royalty thereon.

The invention relates to caseless ammunition, and more particularly to caseless ammunition of the cartridge type for small arms such as military rifles and the like.

Without the advent of caseless ammunition, the problems of both velocity adjustment or correction and complete burn out became acute. Because the amount of molded propellant necessary to achieve a specific velocity is standard, the mold which is shaped to form the propellant can only be utilized in the preparation of one size round or cartridge. For each change in velocity requirement, a new or different size mold has to be provided. The present invention solves this problem by providing an improved caseless cartridge construction with propellant means that can be varied to provide the desired velocity, while utilizing only one size mold. This means also provides more complete burn out in a manner to be described.

It is therefore an object of the present invention to provide improved caseless cartridge type ammunition which has means that can be changed to establish different velocities without change in mold size.

Another object of this invention is the provision of improved caseless cartridge-type ammunition which may be constructed of self-supporting combustible elements and which completely burns out during firing.

Another object of this invention is the provision of improved caseless cartridge-type ammunition which is adapted to use a plurality of combustible elements in concentric relation in each unit thereof for velocity adjustment and complete burn out on firing.

It is a further object of this invention to provide a caseless small arms cartridge that is readily adjustable to velocity requirements and which is of simplified and rugged construction adapted for easy manufacture.

The above objects as well as others together with the benefits and advantages of the invention will be apparent upon reference to the detailed description set forth below, particularly when considered with reference to the accompanying drawing to which attention is directed and in which a cartridge or round of caseless ammunition embodying the invention, is indicated generally by the reference numeral 10. The cartridge 10 includes a central rigid cylindrical support tube 12 of laminated construction comprising a plurality of layers of sheet propellant of the double-base type preferably spirally wrapped. The sheet propellant generally used for this tube is in three or four layers and is a compound mixture of nitroglycerine and nitrocellulose in thin sheet form and known as military M-8.

A projectile, such as a bullet 18, is secured in the forward end 14 of the support tube which is of an inside diameter to provide a tight press fit therewith. A primer cup 20 as a cartridge base, and for ignition, is secured to the rearward end 16 of the tube. The primer cup or base is molded solid from a single-base propellant, such as nitrocellulose and a binder known as military IMR-4809, of relatively fine grain for fast burning, and contains a central primer pocket 22 in its rear or base end in which a standard primer composition 24, such as a lead stephanate composition, is located. The primer cup as a cartridge base is effectively a round and relatively thick disc provided on its upper side with an integral central stud or boss 25 which fits the rear end of the support tube and with a surrounding annular shoulder 26 against which the rearward end 16 of the support tube 12 is firmly seated.

A plurality of explosive propellant discs 28, cut from sheet propellant of the double-base type such as the M-8 above, are stacked on and fit around said support tube 12 and fill the space along the support tube 12 between the primer cup or base 20 and a forward molded annular neck ring 30. The latter is a composition of a single base propellant, such as nitrocellulose and a binder, and is shaped to fit snugly around the forward end 14 of the support tube 12 as indicated. This is of the same outside diameter as the primer cup or base 20 and determines therewith the outside diameter of the cartridge. While the neck ring 30 is molded of the same nitrocellulose single-base propellant material as the primer cup or base 20, it is of a coarser grain so that it is slower burning. This may be a propellant known as military type IMR-4895, for example, which provides the desired grain size.

In order to adjust the velocity capability of the cartridge 10, the number of discs or rings 28 which are used is varied. This is done according to the amount of propellant necessary to achieve a specific projectile or bullet velocity. More discs are used to increase velocity and less discs are used to decrease velocity. Thus with a given propellant composition for the stack of disc charges, such as single base or double base, the ballistic performance of the cartridge can be changed by changing the web or thickness and the number of propellant discs. The complete burn out necessary for the proper functioning of the round is achieved because the plurality of discs, rather than one molded propellant body, provides many more surfaces exposed to the hot combustion gases and hence a faster and complete burn out thereof.

From the foregoing description it will be seen that the cartridge is readily adapted for adjustment to different velocity requirements without change in overall mold size and is adapted for complete burn out. It is furthermore adapted for easy manufacture and assembly. The central support tube 12 provides a support for the projectile 18 and the stack of disc charges 28. It further adds internal strength to the cartridge as a tubular core element, and provides a central combustion space or chamber behind the projectile extending to the base or ignition means 20.

The projectile or bullet 18, which tightly seats in the forward end of the support tube, may be of any required weight and diameter or caliber. By way of example, for 5.56 mm or .223 Remington caliber, the bullet may be .224 inch in diameter and have a weight of 55 grams. For this caliber the overall length of the complete cartridge is approximately 1.5 inches and the body of the cartridge is of a diameter to fit the intended firing chamber, and for this caliber is made to .370 inch.

The molded primer cup 20, seated in the opposite or rear end of the support tube from the bullet, not only provides means for ignition of the propellant stack and support tube in response to detonation of the primer material 24, but also provides a solid base for the cartridge and a seat for both the propellant stack and the support tube.

The body of the cartridge, provided mainly by the stacked propellant discs or disc charges 28, is of the same diameter throughout from the base or primer cup 20 to the neck ring 30 and is molded together with the support tube as a unit. The propellant stack thus provides the main energy for firing the projectile and may be varied while using the same propellant material by changing the number and/or thickness of the discs to change the ballistic performance of the ammunition produced in this way.

The caseless cartridge of the present invention also provides all the advantages common to caseless ammunition types in the saving of brass or other shell metal, which is generally critically short in supply in times of national crises and need, along with a saving of carrying weight for troops and toxic fumes from ejected shells in closed combat vehicles.