US Patent 9551557 Polymer ammunition having a two-piece primer insert

The present invention provides ammunition having a two piece primer insert with a flange, a polymeric middle body extending from the primer insert to a cylindrical middle body coupling region, a polymeric projectile end having a projectile aperture mated to the polymeric middle body, a primer inserted into the primer aperture, a propellant at least partially filling the propellant chamber, and a projectile frictionally fitted in the bullet-end aperture.