Modern long-range AR-15 cartridge. Optimized for high-BC 6mm bullets. Better external ballistics than 6.5 Grendel with less recoil. Fits AR-15 magazines.
Type: Rifle
Introduced: 2020, United States
Parent case: 6.5 Grendel
Standardization: SAAMI
Bullet diameter: 0.243" (6.17 mm)
Case length: 1.491" (37.87 mm)
Overall length: 2.26" (57.4 mm)
Max pressure: 52,000 PSI
Rim type: Rebated
Primer: Small Rifle
Typical twist rate: 1:7.5
Muzzle velocity: 2750–2950 fps
Muzzle energy: 1700–1950 ft-lbs
Effective range: 1000 yd
Common bullet weights: 103, 105, 108, 109 gr
Primary use: Competition, Hunting, Target
Production status: Active
Also known as: 6mm Advanced Rifle Cartridge
History: Introduced by Hornady in 2020, developed with military input for long-range precision in AR-15 platforms. Based on the 6.5 Grendel case necked to 6mm, providing greater case capacity than the 6.8 SPC-derived .224 Valkyrie despite a similar mission. Rapidly adopted by precision rifle competitors and special operations forces.
Notable firearms: AR-15, Howa Mini Action, Ruger American Gen II
Similar cartridges: 6.5 Grendel, .224 Valkyrie, 6mm Creedmoor