SIG SG 551
SIG Sauer AG · Assault Rifle · In Production · 1990
Also known as: SG 551, SG-551, Stgw 90 carbine
Overview
The SIG SG 551 is the carbine variant of the Swiss SIG SG 550 (Stgw 90) assault rifle, chambered in 5.56x45mm NATO. It shortens the barrel to 363 mm (14.3 in) and revises the handguard while retaining the SG 550's gas-operated long-stroke piston action with a rotating, two-lug bolt and its right-side folding stock. Optimized for vehicle carriage and urban or close-quarters operations, the SG 551 omits the bipod, rifle-grenade capability and bayonet lug of the full-size rifle. It is widely fielded by military special forces and law enforcement units, with the popular SG 551 SWAT tactical-rail version aimed at police and special operations.
Specifications
| Weight (empty) | 3400 g (119.9 oz) |
| Overall Length | 833 mm (32.80") |
| Folded Length | 607 mm (23.90") |
| Barrel Length | 363 mm (14.29") |
| Action Type | Gas Operated Long Stroke |
| Firing Mechanism | Hammer Fired |
| Magazine Capacity | 30 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 850 m/s (2789 fps) |
| Effective Range | 400 m (437 yd) |
| Rate of Fire | 700 rpm |
| Barrel Rifling | Right Hand |
| Frame Material | Aluminum |
| Barrel Material | Steel |
| Stock Material | Polymer |
Calibers
- 5.56x45mm NATO · primary · 5.56mm NATO — also known as 5.56 NATO, SS109, .223 Remington (parent)
Features
- Firing modes: Semi Automatic, Full Automatic
- Feed systems: Detachable Box Magazine
- Safety mechanisms: Manual Safety, Fire Selector
- Features: Folding Stock, Rotating Bolt, Gas Piston, Optics Mount, Ambidextrous Controls, Translucent Magazine
Variants
- SIG SG 551 SWAT — Tactical
- SIG SG 551 LB — Long Barrel
- SIG SG 551-1P — Police
Base model
Service history
Operators
- Swiss Armed Forces · adopted 1990 · as Stgw 90 (carbine)
- JW GROM
- French law enforcement units
- Spanish security forces
Production
Production years: 1990-present
Part of the SG 550 series produced by SIG (later Swiss Arms / SIG Sauer AG); the full-size SG 550 was adopted by the Swiss Armed Forces in 1990 with over 600,000 rifles fielded.
Origin
Country of origin: Switzerland
Designer: Jürgen Baumann and Ennio Mattarelli (SG 550 series)
Notes
Selective fire: semi-automatic and full-automatic at ~700 rpm, with an optional three-round burst on some models. Feeds from translucent polymer magazines (10/20/30 round) that can be clipped together side by side. The SG 552 Commando is a further-shortened (226 mm barrel) subcompact derivative.
Background
Developed from the SG 550 that won the Swiss army's service-rifle competition to replace the Stgw 57, the SG 551 carbine became a favorite of European police tactical and special-forces units for its compactness, reliability and accuracy.