The FN SCAR (SOF (Special Operations Forces) Combat Assault Rifle)[3] is a family of gas-operated short-stroke gas piston[4] automatic rifles developed by Belgian manufacturer FN Herstal (FN) in 2004.[5] It is constructed with modularity for the United States Special Operations Command (SOCOM) to satisfy the requirements of the SCAR competition.[6] This family of rifles consists of two main types. The SCAR-L, for light, is chambered in 5.56×45mm NATO and the SCAR-H, for heavy, is chambered in 7.62×51mm NATO. Both types are available in Close Quarters Combat (CQC), Standard (STD), and Long Barrel (LB) variants.

In early 2004, United States Special Operations Command (USSOCOM) issued a solicitation for a family of Special Operations Forces Combat Assault Rifles, the so-called SCAR, designed around two different calibers but featuring high commonality of parts and identical ergonomics. The SCAR system completed low rate initial production testing in June 2007.[7] After some delays, the first rifles began to be issued to operational units in April 2009, and a battalion of the U.S. 75th Ranger Regiment was the first large unit deployed into combat with 600 of the rifles in 2009.[2]