The newly acquired rifles will be deployed by Royal Marines operating within the Littoral Response Groups, which integrate amphibious ships, aircraft, vehicles, and commandos to provide rapid crisis response and special operations capabilities worldwide. This procurement falls under Project Hay, named after World War II Royal Marine fighter ace Ronnie Hay. Project Hay builds on the lessons of Project Hunter, which previously led to the adoption of the Knights Armament Stoner 1 (KS-1) rifle in 2023.
To ensure their effectiveness in extreme environments and high-risk missions, the Royal Marines subjected the new rifles to rigorous live-fire drills and force-on-force exercises.
The SIG Sauer MCX series is a modular firearm family utilizing a short-stroke gas piston system. It is available in multiple configurations, including rifle, carbine, short-barreled rifle (SBR), and pistol variants, catering to military, law enforcement, and civilian users.
The first-generation MCX models include the MCX Patrol (406 mm barrel), MCX SBR (229 mm barrel), and MCX Pistol with stabilizing braces. A specialized military and law enforcement variant, the MCX Low Visibility Assault Weapon (LVAW), features integrated suppression and select-fire capabilities.
The second-generation SIG MCX Virtus, introduced in 2017, features an improved folding and collapsing stock, interchangeable barrels, and an enhanced Matchlite Duo trigger. This lineup includes the Virtus Patrol (406 mm barrel), Virtus SBR (292 mm or shorter), and Virtus Pistol. Additionally, the MCX Rattler, an ultra-compact rifle with a 140 mm barrel, was selected by the U.S. Special Operations Command in 2022 for its personal defense weapon program.
The third-generation SIG MCX-Spear LT, released in 2022, incorporates a lighter handguard, ambidextrous controls, and compatibility with quick-detach suppressors. It is available in 5.56 mm NATO, .300 Blackout, and 7.62x39 mm calibers. 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.
Another variant, the SIG MCX-MR, chambered in 7.62×51 mm NATO, was an unsuccessful contender for the U.S. Army’s Compact Semi-Automatic Sniper System (CSASS) program.
The acquisition of the SIG Sauer MCX rifles marks a significant step in modernizing the Royal Marines' firepower, aligning with the UK’s strategic goals for enhancing its special operations capabilities.
You can watch SIG Sauer Vice President of Marketing Jason Wright's interview with Defensehere.com about the SIG Sauer XM7 and XM250 below:
