SIG SG 540

The SG 540 is a 5.56×45mm NATO assault rifle developed in the early 1970s by Schweizerische Industrie Gesellschaft (SIG, currently SAN Swiss Arms AG) based out of Neuhausen, Switzerland as a private venture primarily destined for export markets and as a potential replacement for the 7.5×55mm Swiss SG 510 automatic rifle known as the Stgw 57 in Swiss service.

SIG SG 540
Class Manportable
Type Rifles
Manufacturer MANURHIN
Origin Switzerland
Country Name Origin Year
Switzerland 1977
Country Name Operational Year Retirement Year
Cameroon View
Chad View
Chile View
Djibouti View
Ecuador View
France View
Gabon View
Ivory Coast View
Lebanon View
Mauritius View
Nicaragua View
Nigeria View
Oman (Muscat) View
Paraguay View
Portugal View
Senegal View
Seychelles View
Switzerland 1977 View
Togo View
Burkina Faso View
Democratic Republic of the Congo View
ManufacturerName Production From Production To Quantity
MANURHIN View
INDEP View
FAMAE View

Work on a new generation of lightweight rifle using the intermediate 5.56mm round began at SIG in the 1960s and resulted in the somewhat unsuccessful SG 530-1 design that employed a gas-assisted roller-delayed blowback operating mechanism which proved too complicated and expensive to manufacture. As a result, in 1969 SIG chose to dispense with the complex roller-delayed action opting instead for a design using the more robust and simple piston-operated rotating bolt locking mechanism (derived from the Soviet 7.62×39mm AK assault rifle). This combination was to be successful and the rifle entered production as a family of weapons consisting of the base 5.56mm SG 540, the 7.62mm SG 542 battle rifle and the 5.56mm SG 543 carbine, where both 5.56mm variants were designed for use with 5.56×45mm NATO M193 ammunition, while the SG 542—the full size 7.62×51mm NATO rifle cartridge.

Production began between 1973–1974, but due to Swiss federal restrictions on firearms exportation, manufacturing had to be carried out at the MANURHIN (Manufacture de Machines du Haut Rhin) facility in Mulhouse, France.

The SG 540 series has entered service with the armed forces of several countries in Africa, Asia and South America as well as numerous law enforcement and security services. In 1988, the nationally-owned Portuguese defense manufacturer INDEP purchased rights to license build the SG 543 carbine for its own forces. Currently both the SG 540 and SG 542 are only manufactured in Chile, under license by FAMAE for the Chilean Armed Forces. Based on the SG 540, FAMAE developed a 9×19mm Parabellum submachine gun version of the weapon known as the SAF.

Type Assault rifle (SG-540, SG-543)
Battle Rifle (SG-542)
Place of origin Switzerland
Service history
In service 1977-present
Used by See Users
Production history
Designer Schweizerische Industrie Gesellschaft (SIG)
Designed 1970s
Manufacturer MANURHIN
INDEP
FAMAE
Produced 1977–2002
Variants SG 542, SG 543
Specifications
Weight SG 540: 3.52 kg (7.76 lb) fixed stock
SG 542: 3.55 kg (7.8 lb)
SG 543: 3 kg (6.6 lb) folding stock
Length SG 540: 950 mm (37.4 in) stock extended / 733 mm (28.9 in) stock folded
SG 542: 1,000 mm (39.4 in) stock extended / 754 mm (29.7 in) stock folded
SG 543: 805 mm (31.7 in) stock extended / 569 mm (22.4 in) stock folded
Barrel length SG 540: 460 mm (18.1 in)
SG 542: 465 mm (18.3 in)
SG 543: 300 mm (11.8 in)
Cartridge SG 540, SG 543: 5.56×45 mm NATO
SG 542: 7.62×51 mm NATO
Action Gas-operated, rotating bolt
Rate of fire 650–800 rounds/min
Muzzle velocity SG 540: 980 m/s (3,215 ft/s)
SG 542: 820 m/s (2,690.3 ft/s)
SG 543: 875 m/s (2,870.7 ft/s)
Effective firing range 100–500 m sight adjustments
Feed system 20- or 30-round detachable box magazine
Sights Rear: rotating diopter drum; front: hooded post

End notes