Multi-piece polymer ammunition cartridge

A polymeric ammunition cartridge having a 2 piece case comprising:

• an primer insert comprising a top surface opposite a bottom surface and a substantially cylindrical coupling element that extends from the bottom surface, a primer recess in the top surface that extends toward the bottom surface, a primer flash hole aperture positioned in the primer recess to extend through the bottom surface, and a groove positioned around the primer flash hole aperture in the primer recess;
• a polymeric middle body comprising a polymeric middle body extending from a body coupling over at least a portion of the primer insert, wherein the polymeric middle body is molded over the cylindrical coupling element and into the primer flash hole aperture and into the groove to form a primer flash hole;
• and
• a polymer nose comprising
• 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 nose junction adjacent to the shoulder on the side wall, wherein the nose junction is a half lap junction that comprises a groove positioned around the side wall and a skirt connected circumferentially about the groove to extend away from the groove and terminates at a point, wherein the nose junction and the skirt are adapted to flushly mate to the body coupling to form a polymeric ammunition cartridge.