The Hornady Subsonic Rifle Ammo 7.62x39 255 gr Sub-X delivers a specialized subsonic option from Hornadys Sub-X series built for hunters and suppressor users who demand reliable terminal performance and controlled velocity; the 255 grain Sub-X bullet carries a lead core and a pronounced cannelure for positive case crimp in semi-automatic platforms, while the Sub-X bullet technologyfeaturing Flex Tip and long grooves in the gilding metal jacket combined with a flat profilepromotes reliable expansion at subsonic velocities, producing substantial muzzle energy of about 624 ftlbs at roughly 1050 fps. The brass-cased, US-origin round is suitable for hunting medium game where noise reduction matters, for range work with suppressed rifles, and for shooters seeking deeper momentum and penetration from 7.62x39mm cartridges; its Sub-X design helps maintain consistent performance in semi-autos and bolt guns alike. If youre comparing subsonic 7.62x39 loads, this Hornady offering stands out for its mass, expansion characteristics, and compatibility with common firearms and muzzle devices.