M40 rifle
Standard USMC sniper rifle from 1966 to 2018.
The M40 is a bolt-action sniper rifle that served the United States Marine Corps through four main versions: the original M40, followed by the A1, A3, and A5. It first entered service in 1966. Every M40 starts as a Remington Model 700 bolt-action rifle, which Marine Corps armorers at Marine Corps Base Quantico then modify using parts from various suppliers. New M40A5s are still being built, and older A1s are upgraded to A3 or A5 standards when they come into the armory for maintenance. Over the years, the rifles have seen many changes in telescopic sights and smaller user modifications. The M40A5 added a detachable magazine and a threaded barrel for attaching a sound suppressor or other muzzle device.
The original M40 was a military-classified version of the Remington 700, made in a factory with a one-piece wooden stock. The M40A1 and A3 switched to fiberglass stocks from McMillan and new scopes, with a trigger pull set at 3 pounds. In 2018, the Marine Corps retired the M40 series and replaced it with the Mk 13 Mod 7.
The need for a standard sniper rifle arose during the Vietnam War. After testing several options, the Marine Corps ordered seven hundred Remington Model 40x rifles—a target and varmint version of the Remington 700—and designated them the M40. Most were fitted with a Redfield 3–9x Accurange variable scope. Over time, problems emerged, especially the wooden stock warping.
In the early 1970s, armorers at Quantico began rebuilding the original M40s into M40A1s. This involved replacing the wood stocks with McMillan A1 fiberglass stocks and swapping the Redfield variable scopes for 10x Unertl fixed-power scopes. The M40 was originally designed by Jack Cuddy and Neil Warren Goddard. The stock included Wichita sling swivels and a Pachmayr buttpad.
The Corps started looking for a replacement for the M40 series in 2004 but didn't draft requirements until 2009, while working with SOCOM. Plans for a "21st century sniper rifle" were paused while the Army's results from SOCOM's Precision Sniper Rifle program were finalized in 2013. The Marine Corps eventually decided to keep upgrading the M40A-series and stick with the 7.62 NATO round, mainly because larger rounds cost more and scout sniper training could achieve kills beyond the weapon's effective range.
In April 2018, the Marine Corps announced it would replace the M40 with the Mk 13 Mod 7.
Quick Facts
- Origin
- United States
- Is Ranged
- yes
- Service
- 1966–present
- Wars
- Vietnam War / Lebanese Civil War / Invasion of Grenada / Gulf War / War in Afghanistan / Iraq War
- Designer
- Remington Arms
- Design Date
- 1966
- Variants
- M40A1 / M40A3 / M40A5
- 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)
- Part Length
- 635 mm (25 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
Facts from the source article.
Lore & Background
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 and gave them the M40 designation. Most had a Redfield 3–9x 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, replacing the original wood stocks with McMillan A1 fiberglass stocks and the original scopes with 10× Unertl fixed-power scopes. The M40 was originally designed by Jack Cuddy and Gunner/Captain/CW04 Neil Warren Goddard.
The M40A3 development began in 1996 and concluded in 2001, when it was placed into service during Operation Enduring Freedom. It served in Operation Iraqi Freedom and other subsequent conflicts. The M40A5 superseded the M40A3 in 2009, incorporating a detachable magazine and a threaded barrel for a sound suppressor or muzzle device. In 2018, the Marine Corps retired their M40s, replacing them with the Mk 13 Mod 7 chambered in .300 Winchester Magnum.
Reader's Guide
The M40 rifle served as the standard sniper rifle for the United States Marine Corps for over five decades, from its introduction in 1966 until its retirement in 2018. It was built from the Remington Model 700 action and modified by USMC armorers, evolving through four main variants to address operational needs. The original M40's wooden stock warped in Vietnam, leading to the M40A1 with a fiberglass stock. Later variants added improved barrels, scopes, and the M40A5 introduced a detachable magazine and threaded barrel for suppressors. The Marine Corps considered a replacement as early as 2004 but continued upgrading the M40A-series, keeping the 7.62 NATO round due to cost and training considerations. The M40 was eventually replaced by the Mk 13 Mod 7, which offered increased range. The M40A6 and M40A7 variants were developed under the Modular Stock Program, with the M40A6 fielded in June 2016, featuring a folding stock and full-length rail.
Did You Know?
- The M40 was originally a military type-classified version of the Remington 700 with a one-piece wooden stock.
- The M40A1 and A3 used McMillan fiberglass stocks and had a trigger pull of 3.
- The M40 was replaced by the Mk 13 Mod 7 in 2018, which is chambered in .300 Winchester Magnum.
More in Bolt-Action Rifles, Part 5 1-24
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