Remington Subsonic, 22 LR, 40 Grain, Copper Plated Hollow Point, 100 Round Box 21137 Subsonic delivers superior stealth and consistency below the sound barrier. Its tack-driving rimfire performance was developed through a joint effort of Remington and AAC team experts, manufactured with tight velocity control to eliminate supersonic cracks. Driving a copper-plated, hollow- point bullet optimized for reduced lead buildup in silencer ports and maximum effectiveness at lower velocity.