SIG Sauer MCX
SIG Sauer · Carbine · In Production · 2015
Also known as: MCX, MCX Virtus, MCX Rattler, MCX Spear, XM7, M7, LVAW, CSAW
Overview
The SIG Sauer MCX is a modular, multi-caliber rifle system developed by SIG Sauer in 2015. Unlike traditional AR-15 platforms, the MCX employs a short-stroke gas piston system with dual recoil springs, eliminating the need for a buffer tube and enabling a fully folding stock. This design allows for exceptional compactness and modularity, with users able to quickly change barrels, calibers, and configurations. The MCX was specifically designed to excel with .300 AAC Blackout for suppressed operations, offering both subsonic and supersonic ammunition capabilities in the same platform. The weapon features AR-15 style controls and accepts standard STANAG magazines, providing familiarity for users transitioning from M4/AR-15 platforms. The MCX has been adopted by elite military units worldwide, including USSOCOM, the Australian Defence Force as their Personal Defence Weapon under LAND 159, and was further developed into the MCX Spear (XM7) selected by the U.S. Army as their Next Generation Squad Weapon.
Specifications
| Weight (empty) | 2700 g (95.2 oz) |
| Weight (loaded) | 3050 g (107.6 oz) |
| Overall Length | 787 mm (30.98") |
| Folded Length | 590 mm (23.23") |
| Barrel Length | 406 mm (15.98") |
| Height | 203 mm (7.99") |
| Width | 71 mm (2.80") |
| Action Type | Gas Operated Short Stroke Piston |
| Firing Mechanism | Hammer Fired |
| Trigger Type | Single Stage |
| Magazine Capacity | 30 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 660 m/s (2165 fps) |
| Muzzle Energy | 1742 J (1285 ft·lbf) |
| Effective Range | 300 m (328 yd) |
| Maximum Range | 600 m (656 yd) |
| Rate of Fire | 850 rpm |
| Barrel Rifling | Right Hand |
| Rifling Twist | 178 mm (7.01") |
| Number of Grooves | 6 |
| Frame Material | Aluminum Alloy |
| Barrel Material | Steel |
| Stock Material | Polymer |
| Finish | Hard Anodized |
Calibers
- .300 AAC Blackout · primary — also known as 7.62x35mm, .300 BLK, 300 AAC Blackout
- 5.56x45mm NATO · 5.56mm NATO — also known as 5.56 NATO, .223 Remington
- 7.62x39mm — also known as 7.62x39mm Soviet, M43
- 6.8x51mm Common Cartridge — also known as .277 SIG Fury, 6.8 Common Cartridge
Features
- Firing modes: Semi Automatic, Full Automatic
- Feed systems: Detachable Box Magazine
- Safety mechanisms: Manual Safety Selector, Firing Pin Safety
- Features: Folding Stock, Modular Design, Suppressor Ready, Picatinny Rail, Ar15 Compatible Controls, Stanag Magazine Compatible, Piston Driven, No Buffer Tube, Quick Change Barrel, Ambidextrous Controls
Variants
- SIG MCX Virtus — Modernized
- SIG MCX Rattler — Compact
- SIG MCX Spear — Different Caliber
- SIG MCX LVAW — Military Special
- SIG MCX CSAW — Military Special
- SIG MCX Spear LT — Lightweight
- SIG MCX Rattler LT — Lightweight
Service history
Operators
- Australian Defence Force · adopted 2022 · as Personal Defence Weapon System
- United States Special Operations Command · adopted 2018 · as SURG/LVAW/CSAW
- United States Army · adopted 2022 · as XM7/M7
- DEVGRU (SEAL Team Six) · adopted 2018 · as MCX LVAW
- 1st Special Forces Operational Detachment-Delta · adopted 2018 · as MCX LVAW
Conflicts
- War on Terror (2015-present)
Production
Production years: 2015-present
Growing military and commercial production; selected as the US Army's Next Generation Squad Weapon (XM7/M7) in the MCX Spear variant
Origin
Country of origin: United States
Notes
The MCX platform's key innovation is its short-stroke gas piston system combined with the elimination of the buffer tube, allowing the stock to fold completely for compact storage and transport. The weapon system is available in multiple calibers including .300 Blackout, 5.56 NATO, 7.62x39mm, and 6.8x51mm (.277 SIG Fury). The .300 Blackout variant is particularly popular for suppressed applications, as the cartridge was specifically designed for this purpose with both subsonic (190-220 grain) and supersonic (110-125 grain) load options. The MCX Rattler is an ultra-compact PDW variant with a 5.5-inch barrel, adopted by SOCOM as the RSAR (Reduced Signature Assault Rifle). The MCX Spear variant in 6.8x51mm was selected as the XM7 rifle for the U.S. Army's Next Generation Squad Weapon program, representing a significant shift in U.S. military small arms.
Background
The MCX's key innovation is eliminating the AR-15's buffer tube by using dual recoil springs above the bolt carrier, enabling a fully folding stock. The MCX Spear variant in 6.8x51mm was selected as the U.S. Army's XM7 Next Generation Squad Weapon in 2022, representing the first fundamental change in U.S. military rifle caliber since the adoption of 5.56mm NATO in the 1960s.