Firearms / Assault rifles / SIG SG-550

SIG SG-550

General Facts

  • TYPE
    Assault rifle

  • ORIGIN
    Switzerland

  • NICKNAMES
    Sturmgewehr 90 / Stgw 90 (Swiss designation in German)
    Fusil d'assaut 90 / Fass 90 (Swiss designation in French)
    Fucile d'assalto 90 / Fass 90(Swiss designation in Italian)

  • DESIGNED
    1978 - 1983

  • DESIGNER
    SIG

  • PRODUCTION
    1986 - present

  • PRODUCERS
    Switzerland - SIG

  • QUANTITY
    Well over 600.000

  • UNIT COST
    Unknown

  • CHARACTERISTICS
    Very reliable
    Very accurate
    High production quality
    Very expensive

Introduction

The SG-550 is a modern assault rifle of Swiss origin. It was developed to replace the elderly SG-510 in Swiss service. The design is based on the SG-540, which was developed by SIG for export. The SG-550 is renowned for its high production quality and good performance.

Design

The SG-550 was derived from the SG-541, which was a higher quality proof of principle based on the earlier SG-540. The SG-550 is gas operated and uses a long stroke gas piston. The receiver, barrel and internal mechanism are made out of metal and the forearm, magazines and the side folding stock out of plastics. Diopter sights are fitted and optics are easily installed.

Firepower

The SG-550 fires the 5.6x45mm GP90 round, which is a Swiss derivative of the 5.56x45mm round. For export sales the SG-550 is available in the 5.56x45mm NATO round with associated faster twist rate. Translucent 20 and 30 round magazines are used. The firing selector alows for single shot, three round burst and full automatic fire at 700 rpm.

Users

The main user of the SG-500 is the Swiss military with over 600.000 rifles adopted. No other nation adopted it as its standard assault rifle. It has been widely adopted by a wide variety of special military and law enforcement units. Due to its production quality and limited age the SG-550 remains in active use.

Variants

SG-552 Commando

The SG-552 Commando was introduced in 1998 and is the shortest version of the SG-550 family. It differs from the SG-550 in having a much shorter barrel and handguard and the recoil spring is mounted differently. During the last production years it was available with a longer barrel as the SG-552 LB. In 2009 the SG-553 was introduced, which is an improved model of the SG-552. It solves several reliability issues of the SG-552 and features the standard SG-550 recoil spring assembly. A SG-553 LB with longer barrel is also available.

TypeAssault rifle
Caliber5.6x45mm GP90 or 5.56x45mm NATO
Magazine5, 10, 20, 30 rounds
OperationGas operated, closed bolt, long stroke gas piston, rotating bolt
Fire selector0-1-3-F
Rate of fire700 rpm
Barrel length226 mm
Rifling250 mm (GP90) or 178 mm (NATO) right hand twist
Muzzle velocity725 m/s
StockFoldable
Length730 mm / 504 mm
Width?
Height210 mm without magazine
Weight3.2 kg
SightsIron sights, hooded post front and diopter rear, 360 mm sight radius, optional optical sights
Remarks-
TypeAssault rifle
Caliber5.6x45mm GP90 or 5.56x45mm NATO
Magazine5, 10, 20, 30 rounds
OperationGas operated, closed bolt, long stroke gas piston, rotating bolt
Fire selector0-1-3-F
Rate of fire700 rpm
Barrel length346 mm
Rifling250 mm (GP90) or 178 mm (NATO) right hand twist
Muzzle velocity?
StockFoldable
Length850 mm / 634 mm
Width?
Height210 mm without magazine
Weight?
SightsIron sights, hooded post front and diopter rear, 360 mm sight radius, optional optical sights
Remarks-
TypeAssault rifle
Caliber5.6x45mm GP90 or 5.56x45mm NATO
Magazine5, 10, 20, 30 rounds
OperationGas operated, closed bolt, long stroke gas piston, rotating bolt
Fire selector0-1-3-F
Rate of fire700 rpm
Barrel length227 mm
Rifling250 mm (GP90) or 178 mm (NATO) right hand twist
Muzzle velocity725 m/s
StockFoldable
Length730 mm / 501 mm
Width?
Height210 mm without magazine
Weight3.2 kg
SightsIron sights, hooded post front and diopter rear, 339 mm sight radius, optional optical sights
Remarks-
TypeAssault rifle
Caliber5.6x45mm GP90 or 5.56x45mm NATO
Magazine5, 10, 20, 30 rounds
OperationGas operated, closed bolt, long stroke gas piston, rotating bolt
Fire selector0-1-3-F
Rate of fire700 rpm
Barrel length347 mm
Rifling250 mm (GP90) or 178 mm (NATO) right hand twist
Muzzle velocity?
StockFoldable
Length850 mm / 631 mm
Width?
Height210 mm without magazine
Weight?
SightsIron sights, hooded post front and diopter rear, 339 mm sight radius, optional optical sights
Remarks-

SG-551

The SG-551 is the carbine model of the SG-550. Its design is identical to the SG-550, but it features a shorter barrel and forearm. The SG-551-1P and SG-551 SWAT are preconfigured rifles for law enforcement use. These models include optics and a cheekpiece on the stock. The preconfigured models are now discontinued since Picatinny rails have become optional. The latest addition is the SG-551 LB which features a longer barrel than the original SG-551, which allows it to mount bayonets and fire rifle grenades. The SG-551 can be fitted with the GL 5140 under barrel grenade launcher.

TypeAssault rifle
Caliber5.6x45mm GP90 or 5.56x45mm NATO
Magazine5, 10, 20, 30 rounds
OperationGas operated, closed bolt, long stroke gas piston, rotating bolt
Fire selector0-1-3-F
Rate of fire700 rpm
Barrel length363 mm
Rifling250 mm (GP90) or 178 mm (NATO) right hand twist
Muzzle velocity850 m/s
StockFoldable
Length833 mm / 607 mm
Width?
Height210 mm without magazine
Weight3.40 kg
SightsIron sights, hooded post front and diopter rear, 100 to 400 m gradation, 466 mm sight radius, optional optical sights
Remarks-
TypeAssault rifle
Caliber5.6x45mm GP90 or 5.56x45mm NATO
Magazine5, 10, 20, 30 rounds
OperationGas operated, closed bolt, long stroke gas piston, rotating bolt
Fire selector0-1-3-F
Rate of fire700 rpm
Barrel length454 mm
Rifling250 mm (GP90) or 178 mm (NATO) right hand twist
Muzzle velocity?
StockFoldable
Length924 mm / 698 mm
Width?
Height210 mm without magazine
Weight?
SightsIron sights, hooded post front and diopter rear, 100 to 400 m gradation, 466 mm sight radius, optional optical sights
Remarks-

SG-550

The SG-550 is the standard full size rifle from which all other versions have been derived. For use as a designated marksman rifle it can be fitted with optics, such as the 4x24mm Kern optics used by the Swiss army. The SG-550 can be fitted with the GL 5040 under barrel grenade launcher and is also capable of launching rifle grenades.

TypeAssault rifle
Caliber5.6x45mm GP90 or 5.56x45mm NATO
Magazine5, 10, 20, 30 rounds
OperationGas operated, closed bolt, long stroke gas piston, rotating bolt
Fire selector0-1-3-F
Rate of fire700 rpm
Barrel length528 mm
Rifling250 mm (GP90) or 178 mm (NATO) right hand twist
Muzzle velocity911 m/s
StockFoldable
Length998 mm / 772 mm
Width?
Height210 mm without magazine
Weight4.1 kg
SightsIron sights, hooded post front and diopter rear, 100 to 400 m gradation, 540 mm sight radius, optional optical sights
Remarks-

SG-550 Sniper

The SG-550 Sniper is a sniper rifle based on the SG-550 rifle. It is also known as the SSG-550 or Sharfsch├╝tzengewehr 550. The SG-550 Sniper is fitted with a longer and heavier barrel which is not fitted with a flash hider. Other adaptations include high quality optics, an adjustable stock, lack of iron sights, adjustable bipod, two stage trigger unit, lack of selective fire, an ergonomic pistol grip and a mirage band. The SG-550 Sniper is one of the very few sniper rifles chambered for the 5.56x45mm round and can be considered the best in its class. The 5.56mm round lack lethality, but allows for very fast follow up shots due to its limited recoil. Due to limited demand for 5.56mm sniper rifles the SG-550 Sniper is no longer in production.

TypeSniper rifle
Caliber5.6x45mm GP90
Magazine5, 10, 20, 30 rounds
OperationGas operated, closed bolt, long stroke gas piston, rotating bolt
Fire selector0-1
Rate of fireSemi-automatic
Barrel length650 mm
Rifling250 mm right hand twist
Muzzle velocity940 m/s
StockAdjustable, foldable
Length1.130 mm / 905 mm
Width?
Height210 mm without magazine
Weight7.02 kg
SightsOptical sight
RemarksFixed foldable bipod

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