M40 rifle

M40
The M40 sniper rifle
Type	Sniper rifle
Place of origin	United States
Service history
In service	1966–present
Used by	United States
Wars	Vietnam War Invasion of Grenada Gulf War War in Afghanistan Iraq War
Production history
Designer	Remington Arms
Designed	1966
Produced	1966–present
Variants	M40A1 M40A3 M40A5
Specifications
Weight	M40A1: 6.57 kg (14.48 lb) M40A3: 7.5 kg (16.5 lb)
Length	M40A1: 1,117 mm (43.97 in) M40A3: 1,124 mm (44.25 in)
Barrel length	610 mm (24 in) (1:12 right hand twist) M40A1: Hart (6 lands and grooves) M40A3: Schneider Match Grade SS No. 7 (6 lands and grooves)
Cartridge	7.62×51mm NATO
Action	Bolt action
Rate of fire	6 RPM
Muzzle velocity	777 m/s (2,550 ft/s) (w/175 gr. M118LR)
Effective firing range	800 meters
Feed system	5-round integral box magazine (M40, M40A1, M40A3) 10-round removable box magazine (M40A5)
Sights	Scout Sniper Day Scope (SSDS)—Schmidt and Bender PM II 3–12×50.

The M40 rifle is a bolt-action sniper rifle used by the United States Marine Corps. It has had four variants—the M40, M40A1, M40A3, and M40A5. The M40 was introduced in 1966. The changeover to the A1 model was completed in the 1970s, the A3 in the 2000s, and the A5 in 2009.

Each M40 is built from a Remington 700 bolt-action rifle, and is modified by USMC armorers at Marine Corps Base Quantico, using components from a number of suppliers. New M40A5s are being built, and A1s are upgraded to A3s and A5s as they rotate into the armory for service and repair. The rifles have had many sub-variations in telescopic sights, and smaller user modifications. The M40A5 incorporates a detachable magazine and a threaded barrel to allow for the use of a sound suppressor or other muzzle device.

The original M40 was a military type-classified version of the Remington 700; it was factory-made, and had a one-piece wooden . The M40A1 and A3 switched to fiberglass stocks made by McMillan, with new scopes. The trigger pull on both models (M40A1/A3) is 3 to 5 lb (1.4–2.3 kg).

During the Vietnam War, the Marine Corps decided they needed a standard sniper rifle. After testing several possibilities, they ordered seven hundred Remington Model 40x rifles (target/varmint version of the Model 700 bolt-action rifle), and gave them the M40 designation. Most had a Redfield 3–9 power Accurange variable scope mounted. With time, certain weaknesses, primarily warping of the all-wood stock, became apparent.

Sometime in the early 1970s, the USMC armorers at MCB Quantico began rebuilding the original M40s into M40A1s. The process involved, among other improvements, replacing the original wood stocks with McMillan A1 fiberglass stocks, as well as replacing the original 3–9× Redfield variable-power scopes with 10× Unertl fixed-power scopes. The M40 was originally designed by Jack Cuddy and Neill Goddard. The stock featured Wichita sling swivels and a Pachmayr buttpad.