English: The United States Navy Mark 12 Mod 0/1 Special Purpose Rifle (SPR) is a rifle that has been in service with the United States special forces in Operation Enduring Freedom and 2003 invasion of Iraq-Operation Iraqi Freedom. This weapon system is a heavily modified deviation from the familiar AR15/M16 line of infantry weapons, and thus is chambered for NATO standard 5.56 x 45 mm caliber ammunition. It serves a light sniper/sharpshooter role.