AR 15 Cal:5.56 / Remington 223

The AR-15 rifle is typically chambered for the 5.56×45mm or .223 Remington military cartridge. Due to the pressure associated with 5.56×45mm, it is not advisable to fire 5.56×45mm cartridges in an AR-15 marked .223 Remington as this could result in damage to the rifle or injury to the rifle Shooters can lead.