Welcome to product of the week, a new feature for the International Military Review where we examine a defence product each week. Products ranging from, anti-aircraft missiles to torpedoes, submarines to ballistic vests and recoilless rifles to communications equipment. This week’s nominee, the SIG Saur P320 comes courtesy of gun designer Adrian Thomele and his team: Thomas Metzger, Michael Mayerl and Ethan Lessard. The firearm, was forged in 2014 within SIG Saur’s American arm – SIG Saur Inc. The Swiss business’s New World enclave is provided by the 14,306 strong town of Exeter, in the far north-eastern state of New Hampshire. The weapon was born a mere stone’s throw from America’s Massachusetts birthplace, just five miles from the state border and currently supplies both civilian and military customers. Today, the SIG Saur P320 is used by nine separate law enforcement forces and agencies across the US, one foreign military and two foreign police forces. It goes without saying that, despite being built only in 2014, its wide ranging impact has already been felt. In 2017, the P320 had allowed the Danish Defence Force to replace their obsolete 1949 vintage SIG 210s. The Danish project which attracted the attention of their neighbours in Norway, who adopted the sidearm in late 2018. An action undertaken to replace 1984’s SIG Sauer P226, for Norway’s national police service. The Police Nationale Francais were also intrigued. A wave of local legislation, including enabling the use of 9mm ammunition, in the wake of 2015’s Charlie Hebdo and the Paris November Attacks, provided an opportunity to integrate P320s into the police. From 2016, 9mm SIG Saur handguns have been introduced to replace the antiquated .38 special round firing Ruger SP101 revolver. A weapon deemed to slow for reacting to sporadic high-intensity confrontations. The weapon’s close-quarters suitability was soon noted by Gallic law enforcement’s elite echelons. An interest which was made manifest in the form of the weapon’s uptake by the Service de la Protection. A 2013 founded organization, responsible for the protection of public figures in the European nation, in an historical line of duty stretching nearly a century to the creation of the Service des Voyages Officiels et de La Securite des Hautes Personnalities (SVOSHP) in 1935.
“Out of this number, 161 had used their M9 sidearm in the tight unforgiving battlespaces of Iraq’s urban landscapes. Of that figure 48% of interviewees were unsatisfied with its general performance.”
The SIG Sauer P320, would likely have remained a low-intensity security weapon had it not been for its entry into the 2015 – 2017 XM17 Modular Handgun System Competition. A contest launched to discover the provider, of the US Army and US Air Force’s new service pistol. The deeper rationale of the search, was to end the increasing complaints from the soldiery around the rapidly decaying M9 Berreta’s battlefield performance. The winter of 2006 saw the first nibbles of a complaints tidal wave beginning to surround the M9 handgun. During December of that year, the Centre for Naval Analysis – looking after the Navy and USMC, conducted a survey of 2,608 soldiers fresh from operations in Iraq and Afghanistan. Out of this number, 161 had used their M9 sidearm in the tight unforgiving battlespaces of Iraq’s urban landscapes. Of that figure 48% of interviewees were unsatisfied with its general performance. A staggering 88% had gripes with its rate of fire, and 54% thought the Italian made handgun to be unacceptably unreliable. It was no surprise then, that when the XM17 competition was announced that among its chief requests was reliability. Alongside this requirement, came a demand for picatinny rails to support accessory attachments, the inclusion of a suppressor option and a need for peak accuracy. When SIG Sauer Inc. sent their candidate to the competition, it went up against five other entries of note. The first was another offer from Beretta, the ultra-modern 2016 built APX, striker fired pistol. The second aspiring firearm came from Belgium in the form of a unique, specialist variant of FN Herstal’s FN FNS handgun. Not to be outdone, the legendary makers of the Glock series followed suit and they offered their own specialised product. Fourthly came the M&P pistol, from Smith and Wesson and lastly a Czech entry from Ceska Zbrojovka – the CZ75.
On a freezing January day in 2017 the SIG Sauer P320 was formally declared the winner of the tournament. It is not difficult to identify the main reason why – the SIG Sauer P320 provides for a far superior user experience in terms of reliability and resilience over the long term. The Swiss handgun, does this by attempting to rectify an inherent problem with all short-recoil operated firearms. A class of firearms which includes almost all sidearms, in addition to some older machine guns. Short-recoil operated weaponry, calls for the weapon’s top slider and barrel to become detached post-shot. The force generated by the exit of the round, generated via the pressurization within a handgun’s chamber through the release of hot gases from the loaded bullet, is not fully dissipated by the removal of the projectile. The mechanism within the pistol, then utilizes Newton’s Third Law of Physics – every action has an equal and opposite reaction, to send the top slider backwards to eject the left-over bullet casing. The barrel stays static, as the casing is removed a space above the magazine – the breech, is freed allowing another round to be loaded into the new gap. The Newtonian forces still working on the slider, sends the slider forward as it reaches its backward apex. The round sitting in the breech becomes chambered, when the slider returns to its forward most position whereupon the recoil force finally expires. Of course, in the field this works far faster, yet there is a single weak point in the system which causes older variants of this action to become increasingly unreliable. The physics involved in detaching the slider and barrel, requires a way to allow the slider and barrel to connect, in a loose but not totally free manner. Traditionally this is done via sets of tight grooves, machined so as the two parts interlock but do not constrain each other.
The short-recoil system depends on these grooves enormously, unfortunately they are notoriously vulnerable to sand, dust and dirt. If the contaminants block the grooves, even in a small way, then the operation of the weapon is made infinitesimally more difficult. The speed of action becomes sluggish due to the extra force needed to force the slider into obstructed spaces, from that comes an unforeseen level of recoil due to the extra force. The firearm will then stray from finely engineered precision settings internally present, making the sights less reliable – tailored as they are to the absolute static nature of the pistol’s finely tuned interior components. The reportedly woeful performance of the M9 by the third year of America’s 21st century adventures in the Middle East, likely has a great deal to do with chronic blockages of the weapon’s grooves. Exposed to fighting in the dusty, sandy, windswept deserts of Mesopotamia and Afghanistan’s dry wadis, placed the M9’s delicate grooves under serious strain. The result was endemic malfunctions, leading to a building reputation of unreliability. The SIG Saur candidate to replace the M9 solves this issue beautifully. In 1975 the Swiss born company, set about rectifying the problem. The first act in the so called SIG Sauer system, was to remove the hypothetically connecting grooves in both the barrel and slide. In the place of grooves the company, built two interlocking metal platforms at the bottom of the slider and top of the barrel. The platforms, would only come apart with the energy released through detonating the round. The metal platforms would then perform the same function as the traditional groove design, but not dependent on the all-too-inviting spaces they present for the gathering of battlefield debris. The consequent weapon is highly reliable. To put the icing on the cake, the weapon can also take three types of round: a standard 9 x 19mm Parabellum round, a heavy .357 SIG Sauer round or an equally devastating .45 ACP round. A loadout complemented by ambidextrous handling and a modular build for ease of repair and maintenance. In terms of feed, the weapon takes ten ACP rounds, fourteen SIG rounds and seventeen Parabellum rounds in box magazine format. Taken together, the SIG Sauer 320 is a graceful, reliable and ultimately effective piece of kit that we shall no doubt see on the battlefield, for decades to come.
SIG Sauer 320 Technical Specifications
Barrel Length: 120mm i.e. 59% of Total Weapon Length
Width x Height: 35.5mm x 140mm
Calibre: 9 x 19mm Parabellum Round
9mm SIG Saur Round. Known as .357
10mm (.40) Smith and Wesson Round
11.5mm (.45) Automatic Colt Pistol round
Firing Mode: Semi-Automatic
Muzzle Velocity: 365 m/s
Feed System: Box Magazine of 10 x .45 ACP rounds
14 x .357 SIG rounds
17 x 9 x 19mm Parabellum Round (NATO)
Sights: Iron Sights with a front blade and rear notch, but has rails for all sorts of stuff
Action: Sig Saur System, Short Recoil