The M40 rifle is an American, bolt-action sniper rifle derived from the Remington Model 700 for the US Marine Corps. The M40 currently has four variants, the newest being the M40A5. The M40A5 features a barrel compatible for a suppressor and detachable magazine. The rifle was used during the Vietnam War and was designated as the standard sniper rifle for the USMC. The M40 is also used by the US Secret Service in limited amounts. The weapon has an effective range of 800 meters and fires the 7.62x51mm NATO.