Hornady Subsonic 7.62x39mm 255 Grain Centerfire Rifle Ammo is designed for reliable expansion below the speed of sound. Subsonic Rifle Ammo utilizes the SUB-X lead-core projectile. Long grooves in its metal jacket combine with the bullet's flat profile and Flex Tip insert within its hollow point cavity to expand reliably at low velocities. Designed to fit, feed, and function in a variety of firearms, including gas system guns. Unique powders are optimized for low flash signature. SUB-X bullet with lead core and Flex Tip Designed for reliable expansion at velocities as low as 900 fps Designed to function in a wide variety of firearms Powders are optimized for low flash signature