A modern AR-15 hunting cartridge introduced by Sharps Rifle Company in 2012 by necking the .223 Remington case up to .257 caliber. Designed specifically to give AR-15 hunters a legal option in the growing number of states that impose minimum caliber restrictions on deer hunting with semiautomatic rifles. SAAMI-standardized in 2015. Functions in any standard AR-15 lower receiver with only a barrel change — the bolt, magazine, and gas system are unmodified.
Type: Centerfire Rifle
Introduced: 2012, United States
Parent case: .223 Remington
Standardization: SAAMI
Bullet diameter: 0.257" (6.5278 mm)
Max pressure: 55,000 PSI
Primary use: Hunting, Target
Production status: active
Also known as: .25-45