Subsonic, 338 ARC, Subsonic, 307 Grain, Sub-XHornady, Subsonic, 338 ARC, 307 Grain, Sub X, 20 Round Box 307 Grain Sub X Bullet 1050 FPS Muzzle Velocity 752 FT LB of Energy Product Description Hornady Subsonic Ammunition designed for accuracy and performance below the speed of sound now comes in both rifle and handgun loads. With high quality cartridge cases and primers, Subsonic Ammunition offers the performance and accuracy shooters have come to expect from Hornady. Specifications UPC