High strength polymer-based cartridge casing and manufacturing method

A method of making a high strength polymer-based cartridge casing comprising the steps of:

• molding a component using a polymer, comprising:
• a first end having a mouth;
• and a second end opposite the first end;
• molding a neck extending away from the mouth;
• molding a shoulder extending below the neck and away from the first end:
• molding a propellant chamber extending below the shoulder, opposite the neck;
• and molding a back end extending below the propellant chamber, comprising:
• an extraction groove and a rim on an end of the cartridge casing opposite the mouth;
• wherein molding the shoulder comprises the steps of:
• forming an outside shoulder sloped at an acute outside shoulder angle in relation to a center axis extending longitudinally along the cartridge and passing through a center of the mouth:
• forming an inside shoulder sloped at an acute inside shoulder angle in relation to the center axis, and separated from the outside shoulder by a shoulder thickness, and uniform over a circumference of the cartridge casing;
• and setting the outside shoulder angle to not equal the inside shoulder angle, and the inside shoulder angle is greater than the outside shoulder angle, wherein molding the neck includes the step of forming the neck to allow a projectile to extend into the propellant chamber past a portion of the inside shoulder.