Description
Hornady Subsonic rifle ammunition addresses the challenge of reliable terminal performance at subsonic velocities, where conventional hollowpoint bullets often fail to expand consistently. The 307-grain Sub-X bullet used in this .338 ARC load is built around a lead core seated in a gilding metal jacket featuring long longitudinal grooves that work in conjunction with the bullet’s flat profile. A patented Flex Tip® insert within the hollowpoint cavity initiates and guides expansion even at the reduced impact velocities characteristic of subsonic loads, producing consistent terminal results without relying on the hydraulic pressure of a supersonic impact.
The .338 ARC (Advanced Rifle Cartridge) chambering is supported by a broad range of rifle manufacturers including Aero Precision, Ballistic Advantage, CMMG, Faxon, PROOF Research, Seekins Precision, Stag Arms, and others, making this load compatible with a wide selection of purpose-built .338 ARC platforms. Propellant selection is optimized specifically for subsonic performance, contributing to consistent velocity, low flash signature, and lot-to-lot consistency. Paired with a suppressor, the already reduced report of this subsonic load is further attenuated, making it well suited for suppressed rifle use. Ballistic data is generated from a 16-inch test barrel.
Key Features
- Caliber: .338 ARC
- Bullet Weight: 307 grain
- Bullet Type: Sub-X Hollowpoint with Flex Tip® insert (lead core, gilding metal jacket with long expansion grooves)
- Muzzle Velocity: 1,050 fps (16″ test barrel)
- Velocity Class: Subsonic
- Muzzle Energy: 752 ft-lbs
- Case Type: Centerfire brass
- Primer Type: Non-corrosive
- Propellant Notes: Optimized for subsonic performance; low flash signature formulation
- Manufacturing Standards: SAAMI spec
- Weight: Not specified
Use Case
- Sub-X Flex Tip® insert promotes reliable hollowpoint expansion at subsonic velocities where conventional hollowpoints may not expand
- Low flash signature powder formulation supports suppressed and unsuppressed operation in low-light conditions
- Purpose-built .338 ARC chambering ensures reliable feeding and headspace conformance in production rifles from Aero Precision, CMMG, Seekins Precision, Stag Arms, and other SAAMI-spec .338 ARC platforms
- Subsonic muzzle velocity of 1,050 fps pairs effectively with suppressors for significantly reduced audible report
- Long grooves in the gilding metal jacket work with the flat bullet profile to support consistent terminal performance at reduced impact velocities
Box / Package Contains
- 20 rounds of factory-loaded .338 ARC 307gr Sub-X Subsonic ammunition





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