The SIG 530 was a Swiss assault rifle developed in the 1960s by Schweizerische Industrie Gesellschaft

Schweizerische Industrie Gesellschaft

Schweizerische Industrie Gesellschaft , or SIG, is the former name of SIG Holding AG, a Swiss company that has been active in various businesses during its more than 150 years of operation. Since the year 2000 the Society has undergone strategic refocus, concentrating on its core compentence in...

 (SIG) to take the then-new 5.56x45mm NATO

5.56x45mm NATO

5.56×45mm NATO is a rifle cartridge developed in the United States and originally chambered in the M16 rifle. Under STANAG 4172, it is a standard cartridge for NATO forces as well as many non-NATO countries. It is derived from, but not identical to, the .223 Remington cartridge...

 round.

Development

Development of the rifle started in 1963 as a joint project between SIG and Beretta

Beretta

Fabbrica d'Armi Pietro Beretta is an Italian firearms manufacturer. Their firearms are used worldwide for a variety of civilian, law enforcement, and military purposes. It is also known for manufacturing shooting clothes and accessories. Beretta is the oldest active firearms manufacturer in the...

. The latter had already cooperated with SIG on the production of the SG 510-4 rifle for Chile

Chile

Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

. Initial prototypes of the 5.56 mm rifle used the delayed-blowback operating system of the SG 510. However, this operating system proved to be problematic with the relatively "weak" 5.56x45mm intermediate cartridge, and the designers were forced to use a gas-operated

Gas-operated reloading

Gas-operation is a system of operation used to provide energy to operate autoloading firearms. In gas-operation, a portion of high pressure gas from the cartridge being fired is used to power a mechanism to extract the spent case and chamber a new cartridge. Energy from the gas is harnessed...

, roller-locked system. In 1968, Beretta ceased development with SIG, and went to work on their own 5.56 mm rifle design resulting in the outwardly similar AR70

Beretta AR70/90

The Beretta AR70/90 is a gas operated self loading assault rifle chambered for the 5.56mm cartridge, and is the standard issue service rifle of the Italian Armed Forces. The weapon also features grenade sights, and is designed to be fitted with a rifle grenade...

. Due to a lack of sales, SIG abandoned the SG 530 in the 1970s in favor of developing the SG 540

SIG SG 540

The SG 540 is a 5.56mm assault rifle developed in the early 1970s by Schweizerische Industrie Gesellschaft based out of Neuhausen, Switzerland as a private venture primarily destined for export markets and as a potential replacement for the 7.5mm SG 510 automatic rifle known as the Stgw 57 in...

series.