Long-time gun maker Remington introduced their bolt-action "Model 700" rifle series in 1962 to the American public and police forces. It was this rifle that went on to form the basis of the US Marine Corps (USMC) standardized sniper weapon - the "M40" during the Vietnam War. These modified versions were "militarized" by USMC specialists out of the Quantico armory and formally adopted for service in 1966. Several changes throughout her production life yielded a handful of variants as described below - all changes making for a more robust and adaptable battlefield system. Amazingly, the original Model 700 is still in production today while the USMC M40 is still in service - having seen published action in the Vietnam War, Lebanon, Grenada, the 1991 Gulf War, the 2001 Invasion of Afghanistan and the 2003 Invasion of Iraq.
The original M40 production mark was simply designated as the "M40". These were identified by their single-piece, all-wooded stocks and standard Redfield 3-9x scopes mounted over the receiver. After warping issues of the wooden stocks became apparent, the "M40A1" mark was introduced which featured the McMillan A1 fiberglass stock and a stainless steel barrel. The Redfield scopes were also dropped and replaced by Unertl types. The "M40A3" appeared in 2001 with a new McMillan Tactical A4 series fiberglass stock and a switch to Schmidt & Bender 3-12x50 Police Marksman II LP scopes with their illuminated reticles. A Schneider Match Grade SS #7 barrel was also introduced and other changes to this mark drove the weapon's overall weight up by approximately 2lbs. These rifles appeared in time to participate in the American invasion of Afghanistan prompted by the events of 9/11 and have been used extensively since. In 2009 there came the latest M40 incarnation - the "M40A5" - which introduced support for the AN/PVS-22 series night vision scopes and detachable box magazines (as opposed to the original's integral box method).
Overall, the Remington M40 mimicked the lines of the original M700 complete with its long-running stock making up the forend (forestock), receiver, pistol grip and shoulder stock. Later production shoulder stocks were padded for some comfort while a rear sling was present along the left hand side. The trigger, protected by an oblong ring, was unobstructed under the receiver. The bolt-handle and ejection port were set to the right side of the body. A second, forward sling was set along the forward-most portion of the forestock to the left side of the body. The barrel was exposed across the top of the forend and appeared more or less smooth and featureless. An optional bipod could be affixed to the forward portion of the forend for stability when tracking/firing. Sights were conventionally mounted over the receiver and there were no backup iron sights present.
The M40 - like the Model 700 before it - makes use of the tried-and-true "turn bolt" manually-actuated bolt-action system. This meant that the weapon required the user to manage the integrated bolt handle assembly after each successive shot, introducing a live cartridge into the firing chamber. Bolt-action systems have been in widespread use since the latter-half of the 1800s and have proven their reliability in the field time and again. The M40 is chambered to fire the 7.62x51mm NATO standard cartridge (.308 Winchester) from a 5-round integral box magazine (except for the aforementioned M50A5 production model which now introduces a more conventional detachable box magazine support). This allows up to five successive shots to be fired after each turn of the bolt and pull of the trigger. The firing action can be traced back to the original though excellent German Mauser-action. Muzzle velocity is listed at 2,550 feet per second with an effective range out to 1,000 meters - of course this may vary based on training, experience and environmental factors. Early versions of the M40 made use of daytime scopes while the latest mark - the M40A5 - introduces support for night vision optics.
Since its inception, the M40 has proven her worth in multiple conflicts, a testament to her excellent design and Remington pedigree. The same Model 700 has also gone on to be selected by the US Army as its modified M24 "Sniper Weapon System" (SWS) which began service in 1988. While both are born from the same M700 system, the USMC M40 utilizes a "short" action system whereas the US Army M24 relies on a "long" action system and this basically effects the choice of standard ammunition used. Additionally, night vision support for the US Army version began "out of the gate" whereas the USMC M40 had to wait until the arrival of the new M40A5 model.
Despite its excellent qualities, the M40's long term future within the inventory of the USMC is somewhat in doubt largely due to changing battlefield requirements and advancing technologies. A concerted effort is therefore being made to find a suitable replacement for the venerable M40 as of this writing (2012) as the USMC attempts to acquire a next-generation sniper weapon system for future USMC sniper generations. As such, USMC authorities are paying close attention to the "Precision Sniper Rifle" (PSR) program undertaken by the United States Special Operations Command section (USSOCOM). The program aims to find a single bolt-action standard rifle for its specialist snipers in .338 caliber and will likely directly influence both US Army and USMC procurement in the near future.
April 2018 - The Remington M40 is set to be replaced in the USMC inventory by the Mark 13 Mod 7 sniper rifle series.