SIG SG 550
SIG Sauer AG · Assault Rifle · Limited Production · 1986
Also known as: Stgw 90, PE 90, Sturmgewehr 90
Overview
The SIG SG 550 is a select-fire assault rifle chambered in 5.56x45mm NATO, produced by SIG Sauer AG since 1986. This Swiss-manufactured firearm reflects the engineering traditions and quality standards of its country of origin, designed to meet the demands of both civilian and professional users in a competitive global marketplace.
Specifications
| Weight (empty) | 4100 g (144.6 oz) |
| Weight (loaded) | 4580 g (161.6 oz) |
| Overall Length | 998 mm (39.29") |
| Folded Length | 772 mm (30.39") |
| Barrel Length | 528 mm (20.79") |
| Height | 210 mm (8.27") |
| Sight Radius | 540 mm (21.26") |
| Action Type | Gas Operated Long Stroke |
| Firing Mechanism | Hammer Fired |
| Trigger Type | Single Stage |
| Trigger Pull | 35 N (7.9 lbf) |
| 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 | 178 mm (7.01") |
| Number of Grooves | 6 |
| Frame Material | Aluminum |
| Barrel Material | Steel |
| Stock Material | Polymer |
| Finish | Phosphate |
Calibers
- 5.56x45mm NATO · primary · 5.56mm NATO — also known as 5.6mm GP90, .223 Remington, 5.56x45mm
Features
- Firing modes: Semi Automatic, Burst 3, Full Automatic
- Feed systems: Detachable Box Magazine
- Safety mechanisms: Ambidextrous Safety Selector, Firing Pin Safety
- Features: Folding Skeleton Stock, Integrated Bipod, Transparent Magazines, Magazine Linking Capability, Rifle Grenade Capability, Bayonet Mount, Tritium Night Sights, Accessory Rail
Variants
- SIG SG 551 — Carbine
- SIG SG 552 — Commando
- SIG SG 553 — Compact
Service history
Operators
- Swiss Armed Forces · adopted 1990 · as Stgw 90
- French Army
- Spanish Armed Forces
- Polish Armed Forces
- Indonesian Armed Forces
- Malaysian Armed Forces
- US Drug Enforcement Administration
Production
Estimated total produced: 600,000 · Production years: 1986-present
Approximately 450,000 units delivered to the Swiss Armed Forces between 1986-1999. Production for military has ceased but civilian variants still available.
Origin
Country of origin: Switzerland
Notes
The Swiss GP90 variant of 5.56mm ammunition is optimized for a 1:10 rifling twist, while export models use the NATO-standard 1:7 twist. The rifle features ambidextrous controls and is capable of mounting rifle grenades and bayonets.
Background
The SG 550 was co-developed by SIG Sauer and Beretta after winning a Swiss military competition in 1983 against the Swiss Federal Arms Factory's W+F C42. The rifle's transparent magazines allow soldiers to visually confirm ammunition count at a glance, and feature interlocking slots that allow magazines to be clipped together for faster reloading.