Federal Premium® Hydra-Shok® has proven itself for self-defense since 1989. Hydra-Shok Deep„¢ builds off the time-tested platform with design improvements that better meet modern performance measurements. The bullet features a more robust center post and a core design that penetrate to optimal depths through the barriers most commonly encountered in self-defense situations. Hits optimum penetration depths through barriers encountered in self-defense situations Iconic center post design has been improved for better, more consistent expansion Specially formulated propellant Extremely reliable primer