338 ARC – 307 gr Sub-X – Hornady Subsonic (82272) – 200 Rounds

Quiet, hard-hitting subsonic performance is the reason the 338 ARC exists, and this is the load that shows it off. This listing is Hornady Subsonic 338 ARC 307 grain Sub-X ammo, MPN 82272, sold as a 200 round bulk case for suppressed AR-15 shooters.

The 307 grain Sub-X bullet is built to expand at subsonic velocity, using a soft tip and a design meant to open reliably even when the bullet is traveling below the speed of sound. Hornady rates this load at 1,050 fps with 752 ft-lbs of muzzle energy, roughly half again the energy of typical 300 Blackout subsonic loads, which is why suppressor owners are moving to the 338 ARC.

The 338 ARC (Advanced Rifle Cartridge) is a newer Hornady cartridge built for the AR-15 platform and standardized by SAAMI in 2025. It fits a standard AR-15 lower with a 338 ARC barrel, a bolt and magazines made for the ARC case family. A common question is whether 338 ARC is interchangeable with 300 Blackout. It is not: the two use different cases and bullet diameters, so only fire this ammo in a firearm marked 338 ARC. The cartridge was designed around suppressor use, and Hornady offers it in both supersonic and subsonic loadings. Its .338 inch bullets range from lighter supersonic hunting loads to heavy subsonic projectiles, so one rifle can cover deer and hog hunting at moderate range as well as quiet suppressed shooting. Subsonic loads may need a suppressor or an adjustable gas system to cycle reliably, so test in your rifle before relying on it. A 200 round case covers tuning and practice.

Hornady Subsonic 82272 is new production ammunition, not reloads, made in the USA. Each cartridge uses a brass case with a boxer primer and is non-corrosive, and the boxer primed brass is reloadable for handloaders. Buying by the case also keeps you on one production lot, so point of impact and velocity stay consistent from box to box. This case comes in factory packaging as 10 boxes of 20 rounds for a total of 200 rounds of 338 ARC 307 grain Sub-X Subsonic.