Abstract: A high strength polymer-based cartridge casing can include a first end having a mouth and a neck extending away from the mouth. Next, a shoulder extends below the neck and away from the first end. An inside of the shoulder can be shaped in at least one of a convex or concave shape. The shoulder can have unequal outside and inside shoulder angles. Further, the inside shoulder can be textured or coated.

Abstract: A high strength polymer-based cartridge casing can include a first end having a mouth and a neck extending away from the mouth. Next, a shoulder extends below the neck and away from the first end. The cartridge can have a frangible portion capable of being split upon discharge of a projectile. A projectile can be disposed in the mouth and a relief can be disposed on the neck near the mouth and projectile. The relief can form a gap between the neck and the projectile to receive an adhesive.

Abstract: An example of a polymer-based machine gun link can include a first side having a finger to hold a cartridge and a second side, opposite the first side, having at least two fingers to hold a second cartridge. A stem can join the first side and the second side the two fingers are smaller than the finger and spaced along the stem so that the finger fits between the two fingers. All of the finger, the two fingers, and the stem are made from polymer.

Abstract: A cartridge for ammunition has a base with an axial end section. An annular wall extends from the enlarged outer peripheral lip section to an opposite end. The axial end section has a primer cavity therein and a radially outwardly extending peripheral extraction lip. An annular ledge is axially positioned at an inner end of said primer cavity and radially extends inwardly from said annular wall. A passage has a reduced diameter compared to the primer cavity and extends through the annular ledge. A main charge cavity is at an opposite side of the ledge from the primer cavity. A knurl section is on an outer surface of said cylindrical wall. A cartridge case is attached to the base about said knurl section.

Abstract: A high strength polymer-based cartridge casing includes an upper component of polymer, a bullet of a standard weight, a lower component of polymer, and an insert. The upper component has a shoulder portion and an upper component inner wall has a first slope extending from the shoulder. The lower component has a lower component inner wall having a second slope. The upper and lower component inner walls form a propellant chamber; and the first and second slopes reduce a volume of the propellant chamber. The reduced volume of the propellant chamber permits only enough propellant to propel a bullet engaged in the cartridge casing at subsonic speeds.

Abstract: A high strength polymer-based cartridge casing can include a first end having a mouth and a neck extending away from the mouth. Next, a shoulder extends below the neck and away from the first end. An inside of the shoulder can be shaped in at least one of a convex or concave shape. The shoulder can have unequal outside and inside shoulder angles. Further, the inside shoulder can be textured or coated.

Abstract: A cartridge for ammunition has a base with an axial end section. An annular wall extends from the enlarged outer peripheral lip section to an opposite end. The axial end section has a primer cavity therein and a radially outwardly extending peripheral extraction lip. An annular ledge is axially positioned at an inner end of said primer cavity and radially extends inwardly from said annular wall. A passage has a reduced diameter compared to the primer cavity and extends through the annular ledge. A main charge cavity is at an opposite side of the ledge from the primer cavity. A knurl section is on an outer surface of said cylindrical wall. A cartridge case is attached to the base about said knurl section.

Abstract: A high strength polymer-based cartridge casing can include a first end having a mouth and a neck extending away from the mouth. Next, a shoulder extends below the neck and away from the first end. The cartridge can be have a frangible portion capable of being split upon discharge of a projectile. The shoulder can have unequal outside and inside shoulder angles. The casing can also include an insert having a rim at one end or a plurality of ribs extending longitudinally along a wall between the shoulder and the bottom of the cartridge and spaced radially from each other around a circumference of the wall. A projectile can be disposed in the mouth and a relief can be disposed on the neck near the mouth and projectile. The relief can form a gap between the neck and the projectile to receive an adhesive.