Ammunition

• US 4,173,186 A
• Filed: 07/07/1960
• Issued: 11/06/1979
• Est. Priority Date: 07/07/1960
• Status: Expired due to Term

• Current Assignee: The United States Of America As Represented By The Secretary Of The Army
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Dunham, James V.
• Primary Examiner(s): Tudor, Harold
• Application Number:
  US04/041,459
• Time in Patent Office: 7,061 Days
• Field of Search: 102/38, 102/43, 102/44, 102/45, 102/93, 102/82, 102/38 R, 42/55, 42/54
• US Class Current: 102/430
• CPC Class Codes: F42B 29/00 Noiseless, smokeless, or flashless missiles launched by their own explosive propellant
• CPC Class Codes: F42B 5/02 Cartridges, i.e. cases with charge and missile

Abstract

1. A cartridge including a substantially rigid extractable case having at e of its ends a head formed to receive a propellant and to provide a primer support adjacent to said propellant, a projectile releasably coupled to the other end of said case, a piston engaging an inner end of said projectile and extending into said casing, said piston having a shoulder near its inner end, a base cup extending into and releasably coupled to said head, said cup enclosing the inner end of said piston with said end spaced from the bottom of said cup, and seal means between the rim of said cup and said shoulder, a second shoulder on said piston in front of the first shoulder, and a shoulder in said case for cooperation with the second mentioned shoulder on said piston in deceleration and deformation of said piston.

Claims

1. A cartridge including a substantially rigid extractable case having at one of its ends a head formed to receive a propellant and to provide a primer support adjacent to said propellant, a projectile releasably coupled to the other end of said case, a piston engaging an inner end of said projectile and extending into said casing, said piston having a shoulder near its inner end, a base cup extending into and releasably coupled to said head, said cup enclosing the inner end of said piston with said end spaced from the bottom of said cup, and seal means between the rim of said cup and said shoulder, a second shoulder on said piston in front of the first shoulder, and a shoulder in said case for cooperation with the second mentioned shoulder on said piston in deceleration and deformation of said piston.

2. A cartridge according to claim 1 wherein the coupling between said projectile and said case is a shear pin.

3. A cartridge according to claim 1 wherein said piston is constituted in part of a material which flows under pressure, and a pusher for said fluid material, said pusher having a longitudinally tapered leading peripheral edge constituting the second mentioned shoulder on said piston, said peripheral edge being in sliding contact with an inner wall of said case.

4. A cartridge according to claim 1 wherein said case has an internal groove and said head encloses a propellant in a skirt extending over said groove and deformable into said groove upon the firing of said propellant whereby said head is locked to said case.

5. A cartridge according to claim 1 wherein said primer support is a recess with an internal groove and supports a primer with its casing extending over and deformable into said groove upon the firing of said primer whereby said primer is locked to said head.

6. A cartridge including a case having at one of its ends a head formed to receive a propellant and to support a primer adjacent to said propellant, said case having an internal shoulder near an opposite end from said propellant, a projectile releasably coupled to said other end of said case, a piston engaging the inner end of said projectile and extending into said casing, said piston having one shoulder near its inner end and another shoulder intermediate its ends for cooperation with said case shoulder, a base cup releasably coupled to said head, said cup enclosing the inner end of said piston with said end spaced from the bottom of said cup, and seal means between the rim of said cup and the first of said shoulders, the outer contour of said piston and the inner contour of said case being similarly tapered at a position longitudinally spaced from said shoulders such that motion of said piston is retarded first by a close fit between said case and piston, second by the crushing the intermediate shoulder of said piston against the internal shoulder of said case and third by engagement between tapered surfaces of said case and piston.

7. In a nearly silent round of ammunition substantially free from flash, said round comprising a case of strong hard substantially non-expandable metal, a propellant carried by said case, a projectile within said case, a piston between said propellant and projectile, and means for holding said piston and projectile against forward movement until pressure of propellant combustion products has reached a predetermined value to insure high velocity of the projectile and piston within a short distance of travel, the combination therewith of means for decelerating the piston within a minor fraction of the distance required for accelerating it, said decelerating means including a peripheral shoulder on said piston, one side of said shoulder being slidable within and in contact with said case, a leading edge of said shoulder forming an acute angle between said side contacting the case inner surface and a leading side sloping toward said piston with said leading edge being spaced from a body portion of said piston, an internal shoulder on said case sloping forwardly and located adjacent a place where deceleration of the piston begins whereby the said spaced leading edge of the piston shoulder is bent radially inward against said case shoulder to provide both a gas seal and a yieldable decelerating effect upon said piston, a body portion of said piston in rear of said first-mentioned shoulder being provided with a relief groove longer than its radial depth and into which material from said piston shoulder flows during its deceleration.

8. A combination according to claim 7 in which the casing and piston are provided with additional decelerating means in front of said cooperating piston and casing shoulders, said last-mentioned means comprising a tapered portion of said piston sloping forward and inward for engagement with the edges of a casing axial perforation of a size to effect a reduction in diameter and rearward flow of metal in said piston tapered portion.

9. A combination according to claim 7 in which said casing shoulder has a more gradual slope on the outside than it has on the inside.

10. A round of ammunition adapted to be fired without a detectable visual or aural effect, said round comprising a substantially rigid cartridge case, a projectile carried by said case, a propellant charge within said case, means whereby said charge may be fired, a piston in said case between said projectile and propellant, a forward portion of said case being provided with a shoulder by means of which said piston may be decelerated, a longitudinally tapered shoulder on said piston adapted to be deformed by said case shoulder and assist in sealing in products of combustion by said propellant as said shoulders engage in decelerating said piston, said piston being provided with a peripheral recess in rear of said piston shoulder and into which said piston shoulder may be at least partially deformed in deceleration, said piston being provided with an O ring on a rear portion, a base cup for compressing said O ring on firing said propellant, the base cup being spaced from a rear end wall of said piston to insure application of propellant pressure to said O ring, a shear pin connecting said projectile and case, said case shoulder being inclined at an angle of about 120°

, a head inserted in a rear end of said case and around said propellant, said head having walls which are thinner and of softer material than said case, and a primer container for insertion in a rear wall of said head, said head wall being provided with a peripheral inner groove into which said primer container material may be expanded, said case and piston being similarly tapered at a position in front of said piston shoulder for assisting in deceleration of said piston and providing an additional tight fit for reduction in danger of gas leakage.