Ballistic sealing, component retention, and projectile launch control for an ammunition cartridge assembly
An ammunition cartridge assembly including a case and a projectile positioned along a longitudinal axis towards the front end of the case. An endcap coupled to the front end of the case is adapted to retain the projectile entirely within the case. A primer is positioned along the longitudinal axis towards the base end of the case. A primer support is coupled to the base end of the case and is adapted to support the primer within the case. A groove is located on the interior surface of the primer support into which the primer expands under pressure during firing. Under firing pressure, the primer is deformed to create a retaining ring that locks the primer to the primer support after the pressure is released. The cartridge assembly includes at least one obturating lip seal to seal at least one of the endcap or the primer support to the case.
1. A telescoped ammunition cartridge assembly, comprising:
a case having a front end and a base end positioned along a longitudinal axis;
a projectile positioned along the longitudinal axis towards the front end of the case;
an endcap coupled to the front end of the case and adapted to retain the projectile entirely within the case;
a primer positioned along the longitudinal axis towards the base end of the case;
a primer support coupled to the base end of the case and adapted to support the primer within the case;
a groove located on an interior surface of the primer support into which the primer expands under pressure during firing, wherein the primer is deformed to create a retaining ring that locks the primer to the primer support after the pressure is released;
an exterior groove located on an exterior surface of the primer support, the exterior groove facing towards an inner surface of the case and providing retention support between the case and the primer support prior to firing;
at least one obturating lip seal to seal at least one of the endcap or the primer support to the case; and
a relief volume of air positioned between the case and at least one of the endcap or the primer support to maintain pressure within the case in the event propellant gasses escape during the initial stages of firing.
2. The telescoped ammunition cartridge assembly of claim 1 , wherein the at least one obturating lip seal comprises an exterior surface exposed to propellant contained within the case, and an interior surface coupled to the at least one of the endcap or the primer support.
3. The telescoped ammunition cartridge assembly of claim 2 , wherein the exterior surface has a larger surface area than the interior surface of the at least one obturating lip seal.
4. The telescoped ammunition cartridge assembly of claim 1 , wherein the projectile includes a mounting groove adapted to face towards an inner surface of the endcap for removeable attachment of the projectile to the endcap.
5. The telescoped ammunition cartridge assembly of claim 4 , wherein the mounting groove of the projectile is coupled to the endcap using an ultrasonic welding attachment.
6. The telescoped ammunition cartridge assembly of claim 1 , wherein the endcap defines a through-hole having a diameter that is sized to receive and retain the projectile prior to firing.
7. The telescoped ammunition cartridge assembly of claim 6 , wherein the endcap includes a stepped interface facing towards the through-hole to control shot start force and to increase firing accuracy.
8. The telescoped ammunition cartridge assembly of claim 6 , wherein the endcap includes a C-shaped portion that is coupled to the projectile, wherein the C-shaped portion is adapted to flex inwards during firing to seal against the projectile body to prevent gas leakage.
9. The telescoped ammunition cartridge assembly of claim 6 , further comprising a relief volume of air positioned within a snap fit and between the case and endcap to maintain pressure within the case in the event propellant gasses escape during the initial stages of firing.
10. The telescoped ammunition cartridge assembly of claim 1 , wherein the primer support is coupled to the case using an ultrasonic welding attachment.
11. The telescoped ammunition cartridge assembly of claim 1 , wherein the groove comprises one of: a continuous indentation on the interior surface of the primer support or a series of indentations on the interior surface of the primer support.
12. An ammunition cartridge assembly, comprising:
a case having a front end and a base end positioned along a longitudinal axis;
a projectile positioned along the longitudinal axis towards the front end of the case;
an endcap coupled to the front end of the case and adapted to retain the projectile at least partially within the case;
a primer positioned along the longitudinal axis towards the base end of the case;
a primer support coupled to the base end of the case and adapted to support the primer within the case;
a groove located on an interior surface of the primer support into which the primer expands under pressure during firing, wherein the primer is deformed to create a retaining ring that locks the primer to the primer support after the pressure is released;
an exterior groove located on an exterior surface of the primer support, the exterior groove facing towards an inner surface of the case and providing retention support between the case and the primer support prior to firing;
a first obturating lip seal to seal the endcap to the case; and
a second obturating lip seal to seal the primer support to the case; and
a relief volume of air positioned between the case and at least one of the endcap or the primer support to maintain pressure within the case in the event propellant gasses escape during the initial stages of firing.
13. The ammunition cartridge assembly of claim 12 further comprising a third obturating lip between the end cap and the projectile.
14. The ammunition cartridge assembly of claim 12 , wherein at least one of the endcap or the primer support is coupled to the case using an ultrasonic welding attachment.
15. The ammunition cartridge assembly of claim 12 , wherein the second obturating lip seal comprises an exterior surface exposed to propellant contained within the case, and an interior surface coupled to the primer support.
16. The ammunition cartridge assembly of claim 15 , wherein the exterior surface has a larger surface area than the interior surface of the second obturating lip seal.
17. The ammunition cartridge assembly of claim 12 , wherein the endcap defines a through-hole having a diameter that is sized to receive and retain the projectile prior to firing.
18. The ammunition cartridge assembly of claim 17 , wherein the endcap includes a stepped interface facing towards the through-hole to control shot start force and to increase firing accuracy.
19. The ammunition cartridge assembly of claim 17 , wherein the endcap includes a C-shaped portion that is coupled to the projectile, wherein the C-shaped portion is adapted to flex inwards during firing to seal against the projectile body to prevent gas leakage.
20. The ammunition cartridge assembly of claim 12 , wherein the groove comprises one of: a continuous indentation on the interior surface of the primer support or a series of indentations on the interior surface of the primer support.