MCX joins KS-1 as Commando Force upgrades its armoury with new rifle

Personnel from the UK Commando Force have been issued a new rifle for specialist operations, including counter-terrorism.

More than 1,500 Sig Sauer MCX rifles have been purchased by the Navy, replacing the L119A1 rifles produced by Colt Canada.

The MCX rifles are designed to complement the Commandos' new general use weapon, the L403A1, better known as the Knights Armament Stoner 1 - or KS-1, that was announced in September 2023.

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The Sig MCX brings a level of versatility well-suited to the unique requirements of the Commando Force, which is tasked with operating in a wide range of extreme environments around the globe ahead of the main allied forces.

Putting the system through strenuous testing has been the Commandos' priority during force-on-force exercises and live firing drills – allowing the future users to train under realistic conditions.

MCX will be used by Commando Force personnel operating with the Royal Navy's Littoral Response Groups.

These bring together amphibious ships, aircraft, vehicles and Commandos under one force that provides a global Crisis Response and Special Operations capability.

The rifle was procured under the auspices of Project Hay – named in tribute to Ronnie Hay, a legendary fighter pilot and Royal Marine of the Second World War.

As the only Royal Marines fighter ace, he flew combat sorties in the Fleet Air Arm, earning multiple decorations for his aerial victories and ground attack missions.

Under the project, Commandos were able to thoroughly field-test systems and provide feedback on their performance.

This was instrumental in shaping the final configurations of the fielded MCX.

User feedback was inspired by Project Hunter, which led to the procurement of the L403A1 rifle.

The MCX is available in a number of configurations and calibres, including 5.56×45mm Nato, 300 AAC Blackout and 7.62×39mm.

It's available in selective fire and semi-automatic only versions, and is in service with various armed forces and police units around the world.

A derivative of the rifle, the Sig MCX Spear, has been adopted by the US Army as the XM7, an assault rile chambered in 6.8mm.