SIG Sauer SIGM400

SIG Sauer SIGM400 series
Sig Sauer M400 series rifle
TypeSemi-automatic rifle
Carbine
Place of originUnited States
Service history
In service2011–present
Used bySee users
WarsWar in Iraq (2013–2017)
Islamic State insurgency in Iraq (2017–present)
Production history
Designed2000s
ManufacturerSIG Sauer
Produced2011–present
Specifications
Mass7.6 pounds (3.4 kg)
Barrel length11.5–20 inches (29–51 cm) (5.56×45mm)
9–16 inches (23–41 cm) (.300 AAC)

Cartridge5.56×45mm NATO
.300 AAC Blackout
ActionDirect gas impingement system, rotating bolt
Feed systemSTANAG magazines

The SIGM400 is a family of firearms manufactured by SIG Sauer.[1] The M400 is an air-cooled, direct impingement gas-operated, magazine-fed carbine based on the earlier AR-15 rifle.[2] It is chambered for either 5.56×45mm NATO or .300 AAC Blackout cartridges, and can have a fixed or telescoping stock.[3]

Design details

Operating mechanism

The SIGM400 is a semi-automatic firearm firing from a closed bolt and uses a direct impingement gas system.[3]

Features

The M400 is offered as either a rifle or as a pistol and is intended for law enforcement, military and civilian markets. Rifles are chambered in either 5.56×45mm NATO with 14.5-inch (37 cm), 16-inch (41 cm), 18-inch (46 cm), or 20-inch (51 cm) threaded barrels, or .300 AAC Blackout with 9-inch (23 cm) or 16-inch (41 cm) threaded barrels. There are California compliant ("featureless") models for both.[3] The .300 AAC Blackout model is tailored specifically for efficient use with suppressors, which SIG Sauer also manufactures.

The SIGPM400 Elite PSB pistol is chambered for 5.56×45mm NATO with an 11.5-inch (29 cm) barrel and is chambered for .300 AAC Blackout with a 9-inch (23 cm) barrel. Both use a Pistol Stabilizing Brace accessory.[3]

Variants

Variants include rifles like the M400 Classic, SRP, Tread, Elite, or Predator, and the Elite PSB pistol.

SIG M400 PRO

The M400 PRO is an improved version of the SIG M400 chambered in 5.56×45mm NATO. Changes include a cold-hammer forged barrel, 2-stage match trigger, free-floated M-LOK handguard, folding front sight, and an updated 6-position collapsible stock.[4]

SIG M400 Tread

The M400 TREAD is a budget-oriented variant of the M400 named for the Gadsden flag and its slogan "Dont Tread On Me". Chambered in 5.56×45mm NATO, it features a 16-inch hammer-forged barrel with a 1:8 twist and proprietary Taper-Lok muzzle threading, mid-length low-profile gas system, 15-inch free-floated handguard,[5] and a Magpul SL-K adjustable stock.[6] The pistol grip can hold AA, CR123A, or CR2032 batteries.[5] Iron sights are not included.

Users

See also

References

  1. ^ "SIGM400". SIG Sauer. Archived from the original on 18 February 2020. Retrieved 13 March 2017.
  2. ^ "SIG SAUER's M400 Predator". gunsmagazine.com. Archived from the original on 14 October 2017. Retrieved 27 February 2017.
  3. ^ a b c d "SIGM400 Predator". sigsauer.com. Archived from the original on 28 February 2017. Retrieved 27 February 2017.
  4. ^ "2019 Defense Strategies: Products" (PDF). SIG SAUER. 2019. pp. 30–31.{{cite web}}: CS1 maint: url-status (link)
  5. ^ a b Massimilian, Andy (30 January 2019). "Review: SIG Sauer M400 Tread". Shooting Illustrated. National Rifle Association. Retrieved 5 December 2025.{{cite web}}: CS1 maint: url-status (link)
  6. ^ "M400 TREAD 1.0". www.sigsauer.com. Retrieved 5 December 2025.
  7. ^ "Conheça os novos fuzis da Polícia Civil do Rio". O Globo. 8 July 2023. Archived from the original on 12 July 2023.
  8. ^ "ISOF Arms & Equipment Part 1 – Personal Equipment". Armament Research Services (ARES). 27 November 2016.
  9. ^ a b "Is This the Ultimate AR-15 Rifle of All Time?". 20 July 2019.
  10. ^ "ORD PABAC2-005-24 Carbine, 5.56mm Assault Rifle 15 Platform Acquisition Project of the Philippine Army".
  11. ^ "Detroit Police Department SWAT Adopts SIG SAUER M400 Rifles | Soldier Systems Daily". Soldier Systems Daily. 19 September 2018. Retrieved 5 December 2025.
  12. ^ "Detroit SWAT picks Sig Sauer M400 in rifle contract".
  13. ^ "Philadelphia SWAT Adopts SIG SAUER M400 Pro Rifles -". 3 January 2019.
  14. ^ "Vermont State Police Adopts SIG SAUER M400 Pro Rifles as Patrol Rifle". www.sigsauer.com. Retrieved 5 December 2025.
  15. ^ "Contract Information". Florida Department of Financial Services. Retrieved 5 December 2025.