Abstract: An ammunition cartridge having a cup-shaped casing. The cup-shaped casing has a closed reward end with a rearward diameter and an open forward end having a forward diameter that is larger than the rearward diameter. A sidewall extends between the peripheries of the rearward end and the top end of the casing. The sidewall tapers from the smaller rearward diameter to the larger forward diameter along a length of a hollow interior of the casing that holds a propellant charge.

Abstract: An automatic or semiautomatic rifle having a short-stroke action with multiple firing chambers which are arranged radially around an axis of rotation parallel to the firing bore. The multiple firing chambers reciprocate rearward and forward while the assembly is indexed through a loading, firing, and ejection sequence. Ammunition cartridges are inserted into the forward end of the chambers and subsequently positioned against the rear of a barrel of the rifle for firing.

Abstract: Provided herein is an automatic or semiautomatic rifle having a short-stroke action. While the stroke-length of the action in conventional weapons is typically 2 to 3 times the length of the cartridge it fires, the stroke-length of the presented rifle may be less than 1.5 times the length of the cartridge it fires. The reduced a stroke-length results in a reduced receiver size and overall weapon length as well as weigh savings. Such a short stroke-length is provided by the use of a divorced chamber that moves relative to the barrel of the rifle. In contrast to existing weapons having a firing chamber that is fixedly attached to the barrel, the firing chamber moves forward and rearward relative to a rearward end of the barrel. In such an arrangement, ammunition cartridges may be inserted in to a forward end of chamber and then positioned against a barrel of the rifle.

Abstract: Disclosed herein is an ammunition cartridge that is nearly 50% shorter and weighs 30% less than a conventional cartridge firing the same projectile. The ammunition cartridge has a generally cup-shaped case with a closed bottom or rearward end having a rearward diameter and an open top end having a forward diameter that is greater than rearward diameter. A side wall extends between a periphery of the close rearward end and the top open end. A top plate is attached about the periphery of the top end of the cup-shaped case. The top plate extends over a portion of the open end of the cup-shaped case. The top plate further includes a raised annular neck defining aperture aligned with the centerline axis of the cup-shaped case. The raised annular neck defines an aperture configured to receive a projectile (e.g., bullet, tracer, etc.).