| SIG MCX | |
|---|---|
 SIG MCX with a skeleton foldingstock | |
| Type | Assault rifle Carbine Semi-automatic rifle |
| Place of origin | United States[1] |
| Service history | |
| In service | 2015–present |
| Production history | |
| Designed | 2013 |
| Manufacturer | SIG Sauer |
| Unit cost | MCX VIRTUS Patrol: MSRP US$2,233 MCX VIRTUS SBR: MSRP US$2,233 MCX VIRTUS Pistol: MSRP US$2,235[2] |
| Produced | 2015–present |
| Variants | SeeVariants |
| Specifications | |
| Mass | 2.61 kg (5.8 lb) (229 mm barrel) 2.72 kg (6.0 lb) (292 mm barrel) 3.6 kg (7.9 lb) (406 mm barrel) |
| Length | 730 mm (29 in) stock unfolded (229 mm barrel) 908 mm (35.7 in) stock unfolded (406 mm barrel) |
| Barrel length | 229 mm (9.0 in) 292 mm (11.5 in)[3] 406 mm (16.0 in) |
| Cartridge | 5.56×45mm NATO .300 AAC Blackout 7.62×39mm |
| Action | Gas-operated short-stroke piston,rotating bolt |
| Rate of fire | 800–900 rounds/min |
| Muzzle velocity | MCX Carbine 5.56×45mm NATO: 3,000 ft/s (914 m/s)[4] |
| Effective firing range | MCX Carbine 5.56×45mm NATO: 1,650 ft (503 m)[4] |
| Feed system | 30-round detachableSTANAGbox magazine |
| Sights | Picatinny rail for mountingiron oroptical sights |
TheSIG MCX is a family offirearms designed and manufactured bySIG Sauer, produced in bothselective fire andsemi-automatic only models, and features ashort-stroke gas piston system, which is inherited from the earlierSIG MPXsubmachine gun. The MCX is available inrifle,carbine,short-barreled rifle, andpistol configurations (the latter configuration generally conforming to the definition of a compactcarbine but for taking apistol brace rather than abuttstock).[5]
The MCX was further developed into theSIG MCX Spear, which was adopted in its.277 Fury chambering as theXM7 rifle by theU.S. Army in 2022.
The SIG MCX was introduced atSHOT Show 2015. The rifle was originally designed by SIG USA, the subsidiary of SIG Sauer based inNew Hampshire.[1]
In 2016, SIG recalled some of the rifles that had the first-generationbolt carrier group.[6]
The MCX has been used by various SWAT teams and militaries, including the Ukrainian Armed Forces during the Russian Invasion of Ukraine.
An MCX was used in the 2016Orlando nightclub shooting, which was the deadliestmass shooting in U.S. history, until exceeded by the2017 Las Vegas shooting.[7]
The SIG MCX series features ashort-stroke gas piston[8] with dual recoil spring system to reduce recoil and improve the reliability of the weapon;[9] this was based on the design of the earlierSIG MPX.[10] The MCX features a system that enables conversion between5.56×45mm NATO,.300 AAC Blackout, and7.62×39mm ammunition, using standard 5.56 mmSTANAG magazines for 5.56×45mm NATO and .300 AAC Blackout, and specially designed STANAG-compatible magazines for 7.62×39mm.[10] The MCX is designed to deliver optimal performance with .300 AAC Blackout and an optionalsuppressor.[11]
The barrel's profile is tapered at the crown to enable the installation of muzzle devices and direct-thread sound suppressors without the use of washers that degrade performance and enables the devices to self-center on installation. The barrel can be changed in a matter of seconds to another length or a different caliber. Additionally the barrels are nitride coated for corrosion resistance.[12][13] It features hardened steel wear points.[10][12]
First generation MCX variants have a forend made of aluminum with aKeyMod system to add accessories while second generation MCX variants have anM-LOK handguard. Controls are mostly ambidextrous including the charging handle but not the bolt release. Sig produces four stock configurations for the MCX carbine.[10][13] The overall layout of the two rifles is similar.[14] SIG designed the upperreceiver to be compatible with standardAR-15 andM16 lower receivers[10][12] with the help of an adapter.[15]
An integrally suppressed upper receiver group based on the MCX was selected byUSSOCOM for the SURG (Suppressed Upper Receiver Group) contract in July 2018. These suppressed uppers would be paired with existing M4A1 lowers in SOCOM inventory.[16][17]
The SIG MCX family has undergone three generations of modifications.
The SIG MCX is available with asafe/semi-automatictrigger group for the U.S. civilian market, or safe/semi-automatic/fully automatic trigger group for themilitary andlaw enforcement agencies.[10]
SIG Sauer offers the MCX in semi-automatic only in three different configurations for the civilian market:
TheSIGMCX Low Visibility Assault Weapon (LVAW) is a short-barreled, suppressed, select-fire variant available only to military and law enforcement agencies. It is nicknamed the "Black Mamba".[21][22]
The SIG MCX VIRTUS is the second generation of the SIG MCX series and was introduced in 2017.
The SIG MCX-SPEAR LT is the third generation of the SIG MCX, introduced in 2022. With the release of the MCX-SPEAR LT, SIG also designed a new, padded, side-folding stock with an FDE finish option to match the rifles, which civilian versions of the rifle variant are sold with. While the civilian version is referred to as the "MCX-SPEAR LT", referencing the SPEAR from which it derives many of its improvements over the MCX Virtus line, SIG Sauer refers to the military versions as simply the "MCX LT" or "MCX Lightweight".[26]
The defining features of the MCX-SPEAR LT are a lightened handguard and barrel design (borrowed from the MCX-SPEAR), an ambidextrous bolt catch and release, a proprietary SL muzzle device to allow for the use of SIG SAUER's quick detaching SLX and SLH suppressors, a custom 28-round AR-pattern magazines when chambered in 7.62×39mm cartridge, and acoyote brown coating (black options are still available for purchase).
The MCX-SPEAR LT is available in5.56×45mm NATO,.300 Blackout and7.62×39mm calibers. The civilian model features 11.5-inch (290 mm) or 16-inch (410 mm) barrel and aPicatinny rail tail interface for attaching either abuttstock or a pistol brace. The military model features both of these options, with the addition of 14.5-inch (370 mm) and 9-inch (230 mm) barrels, as well as a custom two-stage match grade select-fire trigger group.[27][28]
The SIG MCX RATTLER is ashort-barreled rifle variant chambered in.300 AAC Blackout and5.56. It is intended to serve as apersonal defense weapon, featuring a 140 mm (5.5 in) barrel, and comes with aPicatinny rail tail interface for attaching either a compactbuttstock or a folding PCB (pistol contour brace).[29] In February 2018,USSOCOM ordered upper receiver group conversion kits for the MCX Rattler in .300BLK for evaluation.[30]
The MCX Rattler was later selected as the winner of SOCOM's Commercial Personal Defense Weapon (CPDW) contract in May 2022 and suppressed MCX Rattlers will be ordered in 5.56 and .300BLK.[31]
TheSIG MCX Rattler LT is a variant that incorporates the design features of the MCX-SPEAR LT.[32]
The SIG MCX-MR (Mid Range), chambered in7.62×51mm NATO cartridge, was SIG Sauer's unsuccessful submission for theUnited States Army'sCompact Semi-Automatic Sniper System (CSASS) program.[33] The MCX-MR features both anM16/AR-15 typecharging handle and a left side charging handle, a selective fire trigger mechanism, and uses a 20-roundSR-25box magazines. It has an empty weight of 8.9 lb (4.0 kg) and a 406 mm (16.0 in) fluted, 416stainless steelbarrel with a 1:10 inch twist, which is manufactured by Bartlein Barrels. The gas system featuressuppressed and unsuppressed settings. Unlike thehandguard of the MCX, which slides off after pulling the front pivot pin, the MCX-MR requires popping off two screws first.[34]
TheSIG MCX-SPEAR was developed as SIG Sauer's submission for theUnited States ArmyNext Generation Squad Weapon (NGSW) program and is chambered in6.8×51mm SIG Fury cartridge.[35][36][37][38] SIG Sauer was chosen as the winner on 19 April 2022, formerly designated as the XM5, then was later changed to the XM7 and was later typed classified as the M7 in the U.S. military service.[39]
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Australia: MCX Rattler Used by theNSW Police ForceTactical Operations Unit[40] andVictoria Police Special Operations Group in.300 AAC Blackout.[41][42] .300 AAC Blackout variants have been acquired forArmy special forces units since 2024 to replace theH&K MP5.[43][44]
Belgium:DSU[45] and the special response unit of the Ghent local police (COPS).[46]
Canada: Saskatchewan Conservation Officers,[47]Canadian Special Operations Forces Command
Denmark: Jægerkorpset,[48]Rigspolitiet phasing in until 2027.[49]
Estonia: Used by theK-Commando.[50]
France: Groupement de commandos de montagne,27th Mountain Infantry Brigade, 5 in 2021.[51]
Germany:Berlin Police, 300 modified MCXs to meet the police's requirements were ordered in October 2017,[52] plus an additional 160 units for theSEK of Berlin,[53]Landespolizei ofSchleswig Holstein, 531 units delivered, but being replaced with HK 437 because the rifles had shortcomings[54]Rhineland-Palatinate Police: more than 100 rifles ordered in late 2019.[55]
Israel: Used byShayetet 13, theIsrael Defense Forces Naval Commando unit.[56]
Italy: Used byComando Raggruppamento Subacquei e Incursori Teseo Tesei (Frogmen) of the Italian Navy.[57]
Indonesia: Used byKopassus (Special Forces Command) of theIndonesian Army in limited service;Detachment 88 andMobile Brigade Corps of theIndonesian National Police;[58][59][60][61] Also used byKopasgat (Quick Reaction Forces Command) of theIndonesian Air Force;[62][63] andKoopssus (Special Operations Command) of theIndonesian National Armed Forces.[64][65]
Malta: Used by C company, 1st Regiment of theArmed Forces of Malta.[66]
Netherlands: Used by theNetherlands Maritime Special Operations Forces and theDienst Speciale Interventies. The rifles are chambered for .300 AAC Blackout and fitted with the SIG Suppressed Upper Receiver.[67][68]
Poland:Jednostka Wojskowa Grom andJW Formoza acquired the SIG MCX VIRTUS and MCX RATTLER in .300 AAC Blackout with conversion kits to5.56×45mm NATO and7.62×39mm ammunition.[69] Also used byInternal Security Agency[70] andState Protection Service.[71]
Portugal:Polícia de Segurança Pública acquired SIG MCX in 5.56×45mm NATO. Used bySpecial Operations Group (Portugal).[72]
Switzerland: Used by theGeneva Police.[73]
Spain: Used bySpanish Navy[74] andCivil Guard.[75]
Ukraine: Used by theSBUAlpha Group.[76]
Sweden: Used bySwedish Military Intelligence and Security Service National Intelligence Unit.[77]
United Kingdom: Used by thePoliceCounter Terrorist Specialist Firearms Officers including theMetropolitan Police Service[78] andUnited Kingdom Special Forces to replace theHK MP5SD3s.[79] Adopted as the L143A2 byUnited Kingdom Commando Force Littoral Response Group (LRG).[80] In March 2025, 1,500 rifles were ordered for theRoyal Marines.[81][82] The weapon is used with both 5.56x45mm and .300 AAC Blackout ammunition in British military service,[83] with colour-coded accessories being used to ensure that a given weapon uses its correct calibre (tan accessories for 5.56mm weapons and black accessories for .300 AAC Blackout weapons).[84]
United States: various models including the RSAR (Reduced Signature Assault Rifle), LVAW (Low Visibility Assault Weapon) and the CSAW (Close Support Assault Weapon) are used byJoint Special Operations Command.[85] Up to 100 MCXs ordered byU.S. Army through acommercial off-the-shelf contract in December 2018.[86][87][88]
Quotations related toSIG MCX at Wikiquote
