Polymer Ammunition Having a Primer Insert With a Primer Pocket Groove

A polymeric ammunition comprising:

• a primer insert comprising:
• a top surface opposite a bottom surface and a extraction flange that extends circumferentially about an outer edge of the top surface;
• a coupling element that extends from the bottom surface, wherein the substantially cylindrical coupling element is adapted to receive a polymer overmolding;
• a primer recess in the top surface that extends toward the bottom surface, wherein the primer recess comprises a recess bottom and a circular recess side wall;
• a primer flash aperture through the recess bottom that extends through the bottom surface, wherein the primer flash aperture is adapted to receive a polymer overmolding to form a flash hole;
• and a groove in the primer recess positioned around the primer flash aperture adapted to receive a polymer overmolding, wherein the groove extends at least partially over the bottom surface and the groove is adapted to receive polymer at least partially over the bottom surface;
• a substantially cylindrical polymeric middle body extending about the three piece primer insert, wherein the substantially cylindrical polymeric middle body comprises:
• a substantially cylindrical polymeric bullet-end coupling element at a first end of the substantially cylindrical polymeric middle body opposite a substantially cylindrical polymeric coupling end connected by a powder chamber, wherein the substantially cylindrical polymeric coupling end extends over the substantially cylindrical coupling element and covers an circumferential surface of the primer flash hole aperture;
• a substantially cylindrical polymeric bullet-end upper portion comprising a bullet-end coupling element connected to the substantially cylindrical polymeric bullet-end coupling element opposite a projectile aperture adapted to engage a bullet;
• a propellant at least partially filling the powder chamber;
• a primer inserted into the primer recess;
• and
• a bullet frictionally fitted in the bullet-end aperture.