Winchester Supreme Defender PDX1 40 S&W 165gr BJHP Handgun Ammo - Winchester Elite PDX1 Defender, which was chosen by the FBI as their primary service round, features threat stopping technology. It uses a proprietary bonding process for its notched jacket hollow point personal defense expandable (PDX) rounds. PDX1 is engineered to maximize terminal ballistics, as defined by the demanding FBI test protocol, which simulates real-world threats. Elite PDX1 Defender is offered in multiple personal defense calibers. Threat Stopping Technology; Proprietary Bonding Process; Hollow Point; Notched Jacket;