Postwar SMG - the ultimate SMG - the SIG MPX

Postwar SMG - the ultimate SMG - the SIG MPX Postwar SMG - the ultimate SMG - the SIG MPX Postwar SMG - the ultimate SMG - the SIG MPX Postwar SMG - the ultimate SMG - the SIG MPX Postwar SMG - the ultimate SMG - the SIG MPX Postwar SMG - the ultimate SMG - the SIG MPX Postwar SMG - the ultimate SMG - the SIG MPX Postwar SMG - the ultimate SMG - the SIG MPX Postwar SMG - the ultimate SMG - the SIG MPX Postwar SMG - the ultimate SMG - the SIG MPX

We have reached the last post in our ‘Postwar SMG’ series, in which we covered both iconic and virtually unknown designs. Each of the six examples that we presented embodies an unusual feature that sets them apart from the rest. Therefore, in this last post we will provide an overview of significant leaps in SMG design while introducing you to the model which features the most radical improvement since the inception of the SMG concept during WWI, the SIG MPX. Read on for another LSB journey in firearms history…

The history of the sub-machine gun, or machine carbine, is inextricably linked to the early days of aerial warfare in WWI, prior to which the military perceived aircraft as a means of observing the enemy positions and at most, to drop

ordnance on the enemy. During the siege of Tsingtao in China (31 October to 7 November 1914), British and Japanese naval forces were attempting to drive the Germans out of their colony and strategic naval base. Lieutenant Gunther Plüschow flew a Taube aircraft over the blockading squadron and carried out several nuisance attacks. Encountering a Japanese Farman MF.7 aircraft in the air, Plüschow drew his pistol and shot down his opponent, claiming the first aerial victory in aviation history. The stage was set for the arming of aircraft, which initially consisted of providing pilots with effective infantry side arms.

That year, the Italian firm Officine di Villar Perosa designed an unusual machine carbine that was chambered for the 9mm Glisenti pistol round. It was adopted by the military in 1915 to be mounted in observation aircraft. The cartridge was too weak for that purpose and the guns were re-issued to infantry unit, effectively establishing the first use of automatic pistol-calibre carbines by mobile troops. However, it was the Germans who in 1918 developed the concept of the Villar Perosa to create the first dedicated machine pistol of the world, the 9mm Para blowback MP 18,I. Consequently, we consider the MP 18,I as the first milestone in sub-machine gun development.

Arms development in the post-WWI period and WWII was characterised by the development of machine carbines. The most noticeable difference was the transition from early wood-stocked SMGs to the more modern designs, such the German MP 38. In the post-WWII years there were many improvements on the same theme, such as the Israeli UZI, which as we saw in yesterday’s post, employed a telescoping bolt design with the magazine housed in the pistol grip for a compact design. Yet all these SMG were blowback designs mainly firing from an open bolt.

It was the German firm of Heckler & Koch that in 1964 introduced the most significant change in sub-machine gun design since 1918. The MP 5, which we discussed on Wednesday and offered for the first time to collectors and target shooters, was a closed-bolt delayed blowback operated SMG with a roller-delayed bolt derived from the development of Mauser’s StG 45(M) in the last weeks of WWII. The MP 5’s operating system made it much easier to handle than any of its predecessors and it dominated the SMG market in the last three and a half decades of the last century.

Other SMG designs came and went, but none would outdo the MP 5’s technical advantages. Until 2013, when the U.S. branch of the SIG Sauer company designed the SIG MPX, which incorporated a short stroke push-rod gas system and fired from a closed, rotating bolt similar to that used on AR rifles. This revolutionary change in SMG design reduced the recoil and improved the reliability of the firearm. It also avoided the wear and tear inherent of blowback designs. The MPX operating system prevents water or dirt from entering the chamber and causing malfunctions and it permits the use a suppressor with greater ease.

The SIG MPX, which entered production in 2015, features a free-floating barrel, an ambidextrous selector switch for fully automatic or semi-automatic fire and an ambidextrous bolt-catch and a charging handle located at the back or the upper receiver. The latter ensures that cocking the firearm does not interfere with any optics mounted onto the Picatinny rail. One of the most sensible features of the firearm is that it can be mounted with a wide choice of shoulder-stocks, which all attach to a picatinny rail at the rear of the firearm, making the SMG mission-configurable.

The MPX has since progressed into its second-generation production, as approved by USSOCOM (United States Special Operations Command) and incorporating more refinements, such as the MLOK mounts. The combination of its extraordinarily robust design, and its revolutionary operating system and rigorous punishment tests (it is capable of withstanding the pressure from five squibs – you will never experience a cracked frame) makes the MPX the current most significant design milestone in the evolution of the SMG alongside the MP 18,I and the MP 5.

The selective fire SIG MPX is produced in three basic configurations, a standard 8” barrel model, a 6.5” model and a 4.5” MPX-K. They are in service with military and law enforcement units across the world, including with the Malta Police Special Intervention Unit (SIU), which adopted the MPX in 2019.

The range of civilian semi-automatic MPX includes the 4.5” and 8” models, as well as the 16” MPX Pistol Calibre Carbine (PCC), which is an ideal, out-of-the-box solution for dynamic sport shooting. An ultra-compact version (the MPX Copperhead) comes with a 3.5” barrel.

All these semi-automatic models are proudly stocked at LSB and a fresh consignment is expected within the next weeks. If you want to own the best and would like to try out the MPX at the range before taking the plunge, give us a call and we will be pleased to arrange a demonstration.

The SIG MPX models with a barrel length up to 8” are classified as ‘short firearms’ and may be acquired with 20-round magazine if you are in possession of a standard Target Shooter Licence A (or Collector Licence A). The 16” PCC is classified as a long firearm. Hence, the magazine capacity limit is 10-round for the standard licences. You will need the Special licences to purchase these models with a 30-round magazine.

Today’s post is also featured on our Facebook Page. The SIG MPX range is featured on the SIG official website.

We take great pleasure in bringing you these daily snippets of firearms history and we hope that you enjoy reading them. 


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