Hornady's Sub-X Subsonic eXpanding Bullets deliver excellent results without the big, concussive signature. These bullets are designed for maximum penetration, while being delivered below the speed of sound. Sub-X gives you a lead core and long grooves in a gliding metal jacket. Hornady's Flex Tip insert, which fills the hollow point cavity, gives you solid expansion even at low velocities. Cannelures provide a positive case crimp, making Sub-X an excellent performer in semi-autos. Reliable subsonic expansion Flex Tip in hollow point cavity Great in semi-autos