The SIG Sauer 550 serves as the primary service rifle for the Swiss military, and has been since the 1980s. Outside of Switzerland, the 550 has never really caught on as much as the AR-15 or AK-47, but it still has a reputation for being one of the most reliable and finest assault rifles ever made. A version of the 550 called the 556 was briefly made in the United States for a number of years, being virtually except the same rifle except using AR-15 magazines.
SIG Sauer 550 (15/21)
Submitted to "Greatest Rifles of all Time"