US Patent 11047655 Multi-piece polymer ammunition cartridge

The present invention provides polymeric ammunition having a generally cylindrical neck having a projectile aperture at a first end, a shoulder comprising a shoulder top connected to the generally cylindrical neck opposite a shoulder bottom, a side wall extending from the shoulder, a groove positioned around the side wall, a skirt connected circumferentially about the groove to extend away from the groove, wherein the groove and the skirt are adapted to mate to a polymer cartridge.