Hornady's AR-15 compatible .338 caliber cartridge offering both supersonic hunting performance and 1.6x the subsonic energy of .300 Blackout.
Type: Rifle
Introduced: 2025, United States
Parent case: 6mm ARC
Standardization: SAAMI
Bullet diameter: 0.338" (8.59 mm)
Case length: 1.3" (33.02 mm)
Overall length: 2.26" (57.4 mm)
Max pressure: 52,000 PSI
Rim type: Rebated
Primer: Small Rifle
Typical twist rate: 1:8
Muzzle velocity: 1000–2450 fps
Muzzle energy: 444–2660 ft-lbs
Effective range: 600 yd
Common bullet weights: 200, 215, 250, 300 gr
Primary use: Military, Tactical, Hunting
Production status: Active
Also known as: .338 Advanced Rifle Cartridge
History: Introduced by Hornady in 2025 as a direct competitor to the 8.6 Blackout. Designed to function in AR-15 platforms with a standard bolt face. Targets both military special operations and civilian hunting markets with one cartridge covering the spectrum from suppressed subsonic to 600-yard supersonic.
Notable firearms: Various AR-15 platform rifles (in development)
Similar cartridges: 8.6 Blackout, .300 AAC Blackout, .338 Federal