SIG SG 550
Schweizerische Industrie Gesellschaft (SIG) · Assault Rifle · In Production · 1986
Also known as: Stgw 90, Sturmgewehr 90, Fass 90, PE 90
Overview
The SIG SG 550 is a Swiss gas-operated, selective-fire assault rifle chambered in 5.56x45mm NATO. Adopted by the Swiss Armed Forces as the Sturmgewehr 90 (Stgw 90), it uses a long-stroke gas piston driving a rotating bolt and is known for its exceptional accuracy, cold-hammer-forged barrel, translucent polymer magazines that can be clipped together, an integral folding bipod, and a folding stock. It remains the standard service rifle of Switzerland and is renowned among military rifles for its precision.
Specifications
| Weight (empty) | 4100 g (144.6 oz) |
| Overall Length | 998 mm (39.29") |
| Folded Length | 772 mm (30.39") |
| Barrel Length | 528 mm (20.79") |
| Sight Radius | 540 mm (21.26") |
| Action Type | Gas Operated |
| Firing Mechanism | Hammer Fired |
| Trigger Type | Single Action |
| Magazine Capacity | 30 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 911 m/s (2989 fps) |
| Muzzle Energy | 1700 J (1254 ft·lbf) |
| Effective Range | 400 m (437 yd) |
| Rate of Fire | 700 rpm |
| Barrel Rifling | Right Hand |
| Rifling Twist | 254 mm (10.00") |
| Number of Grooves | 6 |
| Frame Material | Steel |
| Barrel Material | Steel |
| Stock Material | Polymer |
| Finish | Phosphate |
Calibers
- 5.56x45mm NATO · primary · 5.56 NATO — also known as .223 Remington, 5.56mm NATO
Features
- Firing modes: Semi Automatic, Burst 3, Full Automatic
- Feed systems: Detachable Box Magazine
- Safety mechanisms: Manual Safety, Fire Selector
- Features: Folding Stock, Rotating Bolt, Gas Piston, Translucent Polymer Magazine, Bipod, Diopter Sights, Cold Hammer Forged Barrel
Variants
- SIG SG 551 — Carbine
- SIG SG 552 Commando — Compact Carbine
- SIG SG 553 — Carbine
- SIG SG 550 Sniper — Designated Marksman
Service history
Operators
- Swiss Armed Forces · adopted 1990 · as Sturmgewehr 90 (Stgw 90)
- French National Gendarmerie
- United States Drug Enforcement Administration
Production
Production years: 1986-present
Over 600,000 rifles produced for the Swiss Army alone; widely exported and licensed.
Origin
Country of origin: Switzerland
Designer: Schweizerische Industrie Gesellschaft (SIG)
Notes
Swiss-issue Stgw 90 rifles include a three-round burst setting in addition to semi- and full-automatic fire. The translucent magazines feature studs and slots allowing them to be locked side by side for faster reloads.
Background
Developed to replace the Swiss Stgw 57, the SG 550 was adopted in 1990 as the Stgw 90. Under Switzerland's militia system, every serving soldier is issued one and keeps it at home, making it one of the most widely held service rifles among a national population.