Better than AR-15, Sig Sauer assault rifles meet the requirements of special forces

PANAGYURISHTE, (BM) – The American division of the world-famous German company, manufacturer of small arms Sig Sauer, part of the Swiss holding Lüke & Ortmeier Gruppe, in 2015, at the Shot Show in Las Vegas, announced its new product – a modular and multi-caliber assault rifle (automatic) – SIG MCX, created on the basis of the previously released submachine gun – SIG MPX.

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And the army, automatic and civilian, self-loading variants were presented simultaneously. The SIG MCX assault rifle was primarily created to meet the requirements of special operations forces and quickly became known in the world of firearms.

The SIG MCX rifle is available in the following 3 versions:

  • SIG MCX SBR – a rifle with a 9-inch barrel and a folding frame butt;
  • SIG MCX Carbine – an army carbine with a 16-barrel barrel – SIG MCX Pistol W / PSB – a rifle with a 9-inch barrel and a folding multifunctional butt with the ability to mount on the forearm of the shooter.

All three SIG MCX versions can use 5.56 × 45 NATO, .300 BLK, and 7.62×39 ammunition. For military-police versions (i.e., automatic), barrels of the following lengths are produced: 6.75 inches and 9 inches chambered for .300 BLK, 11.5 inches, 14.5 inches and 16 inches under the cartridge 5.56 × 45 NATO.

The very idea of ​​an SIG MCX assault rifle (assault rifle) implies a highly modular design, allows for the quick replacement of caliber, various lengths and types of barrels, stocks and other accessories, both domestic and third-party manufacturers.

And all this is a miracle, built with maximum attachment to the habits, and especially of American shooters (well, NATO partners, of course), while maintaining the overall layout, placement of controls and ergonomics as close as possible with the M16 / AR15 family of rifles.

At the same time, the standard (standard) receiver of the SIG MCX rifle, the so-called upper receiver, made of high-strength aircraft aluminum and anodized, assembled with the barrel, bolt group and return mechanism is compatible with standard (Mil-Spec) kits, that is, lower receiver, the M16 / AR15 family, and which can be installed on Mil-Spec AR15 lower receiver assault rifles instead of factory or standard ones.

Read more: The German SIG Sauer branch is expected to end its operations this year

But what is interesting, by design, the SIG MCX rifle is a completely independent weapon and many of its components, such as the upper part of the receiver, the barrel, the bolt group, individually, are not interchangeable with the corresponding units of the M16 / AR15 family.

Structurally, the SIG MCX assault rifle (automatic) and a carbine based on it use gas exhaust automatics with a short stroke of the gas piston, and here, it becomes clear why the SIG software from which the rifle was created was made with automation that is rarely used for the software.

An example now known is making money on popular products by replacing problematic components with more proven ones. Quick-change barrels fixed in the receiver with two transverse screws hidden under a removable fore-end are made in different lengths and calibers, and can also be equipped with special muzzle brake compensators with mounts for SIG Sauer branded quick-release mufflers or other manufacturers, or threaded for installing special integrated silencers, partially hidden inside the forearm.

The trunks are freely hung, with chrome channels and are made according to military standards (MIL-STD-1913). For additional protection, the trunks are treated with a special Nitride coating. The design of the SIG MCX provides for the possibility of changing the barrel, moreover, this can be done in the field and without a set of special tools.

The gas block with a piston and a regulator are mounted on the barrel, which allows optimizing the gas engine for each version of the caliber and barrel length.

The bolt group of the SIG MCX rifle consists, in fact, of the bolt frame, a rotary bolt installed in it, which locks the barrel clutch and a removable pusher, which, in turn, transmits momentum from the gas piston to the bolt frame.

Read more: Supplies of new SIG Sauer assault rifles and machine guns for the US Army began

The pusher is removable and interchangeable, since different barrel lengths mean different distances from the gas piston to the bolt frame. Two return springs are located around their guide rods, and are placed above the shutter inside the receiver.

In case of incomplete disassembly of the rifle (field strip), the bolt group, together with the springs and the guide rods, are removed from the weapon with an integral module. The receiver consists of two parts made of high-strength aircraft aluminum with anodizing of the upper and lower receivers connected by two transverse pins.

In the upper part of the receiver is a bolt group with a return mechanism, a barrel and an aluminum fore-end of a modular design are attached to it. The forend function is performed by a lightweight aluminum frame construction, which is attached directly to the lower and upper receivers and is fixed with a pin in front of the lower receiver, to which the shooting accessories are mounted via the KeyMod interface.

A 30 cm Picatinny rail (MIL-STD-1913) is integrated into the upper part of the SIG MCX module. On the right side of the upper receiver there is a sleeve ejection window equipped with a protective metal shutter to prevent dust and dirt from entering. The shutter is spring-loaded and mechanically synchronized with the movement of the shutter – it opens when the shutter is cocked.

The lower receiver SIG MCX is made with an integrated trigger guard and, thanks to its size, allows the use of shooting gloves. In addition, in the lower part of the receiver are the trigger mechanism and receiver stores, attached to it butt and pistol grip.

The SIG MCX rifle is equipped with pistol grips and SIG Sauer own-made stocks, while the lower receivers of both rifles are structurally capable of using any AR-15 standard pistol grips.

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Handles are made of polymer, with a convenient angle of the handles in the rifle, and are made of anti-slip materials. The arms inside are hollow and can be used as pencil cases.

Interchangeable stocks, three types:

  • folding sideways
  • telescopic, like M4 carbine,
  • telescopic with thin steel guide rods.

The main butt, if you can call it that, the SIG MCX rifle, is a folding folding butt and is equipped with a hinge that acts as a retainer.

Folding the stock is done to the left side, for this it is necessary to raise the stock frame up, free from fixation and fold the stock. The shoulder rests of the stocks are equipped with shock absorbing rubber pads.

Bilateral weapons controls – classic for the family, T-shaped cocking handle with a bolt like an M16 rifle. The three-position (for the automatic version) and two-position (for the civilian) fuse switch on the SIG MCX are made in a two-sided version, directly above the fire control handle. The location of the switch and its operating positions allow you to quickly set the carbine ready to fire.

When fused, the trigger locks. Key extraction shop on the SIG MCX two-way placement. The key layout is standard for the AR15 “family” layout – the key is located above the magazine receiver shaft, in front of the trigger guard and to press it, you just need to remove the index finger from the trigger without taking your hand off the handle.

On the left side of the central part of the lower receiver on the SIG MCX is a shutter delay button. Its placement is also standard for the AR-15 line. The functionality of the key on the SIG MCX, in addition to removing the shutter lag, allows the shutter lag to be set, for which you need to press the enlarged area of ​​the lower part of the key, after releasing the shutter back with the cocking lever. Setting the bolt delay also occurs at the end of the ammunition.

Read more: Top 5 best assault rifles in the world

SIG MCX assault rifles and carbines use detachable magazines compatible with the M16 / AR15 family, as well as STANAG magazines for 5.56 × 45mm NATO and .300 AAC Blackout cartridges and adapted STANAG-compatible for 7.62 × 39 cartridge. Sights are mounted on Picatinny rails on the receiver and forend.

Automatic variants of the SIG MCX are offered for arming various government services, police, special operations forces. Self-loading options are offered for sale in the civilian market as sports, hunting weapons and weapons to protect the home.

To improve its products, SIG uses feedback from special operations units around the world. Noteworthy is the situation with the tender for a new rifle for the army in Germany.

The SIG MCX rifle is used by some special units of the German police, but a demonstration incident happened with the Bundeswehr (German Ministry of Defense) tender – the company itself, after announcing its rifle for the tender, later removed it, stating that the tender conditions were “tailored to one specific model “referring to the new modular HK433

The latter is a joint brainchild of Rheinmetall and Steyr Mannlicher (Rheinmetall – Steyr 5.56), which is a further development of the STM-556 carbine, introduced by the Austrian arms company Steyr Mannlicher in 2012 and clearly does not pass.

Haenel Mk 556 – from a not very well-known player who, nevertheless, already supplies the Bundeswehr with a sniper rifle in .338LM caliber, but at the same time, the company is owned by the emirate company Tawazun – there are also not many chances.

Apparently, the issue of lobbying money plays a paramount role. Conclusion – while maintaining national interests, nevertheless, there is bias …

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