The service life of a military issue handgun is often defined by two things. For an individual weapon, the number of rounds it has fired will eventually take its toll; for an entire model of pistol, however, it is changing times - not just the simple passing of years - that typically forces its retirement.
For the venerable .45 calibre M1911, which had served US forces through every conflict from the First World War to Vietnam and beyond, that moment came in 1985. Now it seems the US Army has decided that the time is right to replace the pistol which succeeded it back then, the 9mm Beretta M9.
Experience, principally in Iraq and Afghanistan, has heavily influenced the list of requirements for the new gun. The army's original request for information released back in 2013 called for "potential improvements in handgun performance in the areas of accuracy and dispersion out to 50m, terminal performance, modularity, reliability, and durability in all environments."
In design terms, that comes down to overcoming many of the perceived shortcomings of the M9, such as its lack of an accessory rail to mount alternative aiming systems, large fixed grips and poor sighting in low light. Its open-slide design has come in for criticism too, the exposed barrel potentially risking allowing the ingress of sand and mud into the mechanism, and soldier feedback has also suggested that the gun does not hit hard enough - although this is, of course, a feature of the standard 9x19mm NATO calibre round that it fires, rather than the weapon itself.
Modular handgun system
The upshot of all of this leaves the army looking for a reliable, hard-hitting pistol that is ergonomically designed with variable grips, can be comfortably fired by shooters of all sizes, and can be customised and accessorised as required.
The XM17 Modular Handgun System (MHS) competition to find it is set to get underway this year and will be worth an expected $580m to the eventual winner. The full list of participants will not be known until after their entries have been formally submitted, but some - including Beretta, Smith and Wesson, Sig Sauer, FN Herstal and Glock - have already declared their interest, and others are expected to follow.
With a lucrative government contract up for grabs and a huge potential sales boost in the wider defence and civilian markets almost certain to follow in its wake, this is shaping up to be a hot contest between some of the world's premier gun-makers and best modern firearm designs.
A year ago, Beretta unveiled a range of improvements and upgrades including a modular wrap-around over a thinner base grip, an accessory rail, replaceable sights and a suppressor-threaded barrel to extend the M9's useful life more cheaply than total replacement. Rejected at the end of January 2015 on the basis of a cost-benefit analysis and a perceived inability to meet the new requirements adequately, Beretta is now expected to put a variant of its all-new APX up for consideration.
Designed specifically for military and law enforcement markets and three years in the development, the polymer-framed APX represents a step-change in design from the previous M9 and is the first full size pistol from the company to be striker-fired.
Smith and Wesson M&P
Smith and Wesson, in partnership with General Dynamics Ordnance and Tactical Systems, will be offering a version of its M&P (military and police) polymer-framed, striker-fired model for evaluation. The reputation of the M&P recently gained a notable boost following its performance in Bureau of Alcohol, Tobacco and Firearms tests, which ultimately led to it being adopted, in .40 calibre, as part of an $80m contract.
With a host of safety features, an integrated accessory rail, a modular grip system and a self-cleaning, enclosed-slide design, the M&P is widely tipped as one of the frontrunners in the competition.
Sig Sauer P320
Sig Sauer products sit in a number of US armed forces' holsters already; the US Coastguard and Department of Homeland Security Office of Immigration and Customs (ICE) use the P229, while the P226 is carried by many Navy SEALs. For the MHS competition, the company will be putting forward one of its P320 models.
This pistol is a variant of the company's P250, using a striker firing mechanism instead of a double-action external hammer. A truly modular design based around a stainless steel frame/fire control unit, the P320 comes with three glass-reinforced polymer grip options, an integral Picatinny mounting rail, interchangeable trigger shoes and a host of built-in safety options.
In 1980, the performance of the then-revolutionary 'plastic' Glock in the Austrian Army's competition to replace its ageing Walther P38s surprised the gun industry. Subsequently in service with a range of military and police forces across the world, including the UK, and now in its fourth generation, the Glock 17 is a striker-fired weapon with a unique nylon-polymer frame.
The company designed the Glock 21 SF, a short framed model to enter the 2005 Joint Combat Pistol trial - an earlier, cancelled programme to replace the M9 - which featured many of the elements required for the forthcoming MHS competition. Although there has been no official word from Glock about its intended submission, it is likely that the company's entry will draw on this previous experience.
The FN Herstal also developed its FNX pistol to meet the requirements of the cancelled Joint Combat Pistol competition, complete with its accessories rail to mount lights or laser sighting aids as required and interchangeable back-straps to customise its grip. Unlike most of the designs expected to contest the MHS trials, the FNX bucks the trend towards strikers retaining an external hammer, and can be fired in both single- and double-action modes.
For traditionalists on the panel its safety mechanism is particularly appealing; based on the M1911 design, it allows the weapon to be carried in condition one - "cocked and locked" with the hammer back and the safety engaged for a fast first shot.
The company has not made a formal announcement to date about its entry, but the FNX looks the most likely contender in the current FNH product range.
Big bullet debate
The stopping power of its side-arms is a sensitive issue for the US Army. During the Philippine-American War, the limited success of the .38 Long Colt round against drug-hyped Moro tribesmen led to the temporary return of the old .45 Colt calibre M1873 single-action revolver, and ultimately resulted in the adoption of the much-loved M1911 semi- automatic itself.
Despite the standardisation of the 9mm as the NATO pistol round, America's love of the 'big bullet' never really went away - as the US Marines' choice of the new Colt M45A1 close quarter battle pistol clearly shows. For the MHS competition, the army is deliberately throwing the net wide, leaving the choice of round up to the manufacturers and allowing them to submit entries in two different calibres if they wish.
With all of the likely candidates chambered for a range of cartridges - including 9mm, .40SW, .357SIG and .45ACP - and recent advice from Pentagon lawyers allowing expanding or fragmenting ammunition to be considered alongside conventional full metal jackets for the new weapon, choosing the M9's eventual successor really will come down to finding the best combination of gun and bullet.