U.K. Orders 1,500 Sig Sauer MCX Rifles for Royal Marines

The U.K. Navy has ordered more than 1,500 Sig Sauer MCX rifles for the Royal Marines as part of a £6 million investment in the Commando Force.

The Sig Sauer MCX rifles will replace the current models produced by Colt Canada. The new weapons are intended for specialist operations, including counter-terrorism, and will be used by Royal Marines operating with the Littoral Response Groups. These groups combine amphibious ships, aircraft, vehicles, and commandos to provide a rapid crisis response and special operations capability worldwide.

The rifles were procured under Project Hay, named after World War II Royal Marine fighter ace Ronnie Hay. Project Hay emphasizes advanced equipment for modern operations, building on lessons learned from Project Hunter, which led to the adoption of the Knights Armament Stoner 1 (KS-1) rifle in 2023.

Royal Marines tested the new rifles through live-fire drills and force-on-force exercises to ensure their suitability for extreme environments and high-risk missions.

The SIG MCX is a firearm family by SIG Sauer with a short-stroke gas piston system, available in rifle, carbine, short-barreled rifle (SBR), and pistol configurations for civilian, military, and law enforcement use.

The first generation includes the MCX Patrol (406 mm barrel), MCX SBR (229 mm barrel), and MCX Pistol with stabilizing braces. The MCX Low Visibility Assault Weapon (LVAW) is a suppressed, select-fire model for military and law enforcement.

The second generation, SIG MCX Virtus (2017), features a folding and collapsing stock, interchangeable barrels, and a Matchlite Duo trigger. It includes the Virtus Patrol (406 mm barrel), Virtus SBR (292 mm or shorter), and Virtus Pistol with a stabilizing brace. The MCX Rattler is a compact, short-barreled rifle (140 mm barrel) in .300 Blackout and 5.56 mm, selected by U.S. Special Operations Command for its personal defense weapon program in 2022.

The third generation, SIG MCX-Spear LT (2022), has a lighter handguard, ambidextrous controls, and supports quick-detach suppressors. It comes in 5.56 mm NATO, .300 Blackout, and 7.62x39 mm, with civilian and military barrel options. The SIG MCX-Spear, chambered in 6.8×51 mm SIG Fury, was adopted as the XM7 rifle by the U.S. Army in 2022.

The SIG MCX-MR, chambered in 7.62×51 mm NATO, was an unsuccessful entry for the U.S. Army’s Compact Semi-Automatic Sniper System (CSASS) program.