Sk-FSR

The TERRACOR Federal Standard Rifle, under the official designation Sk-FSR (Sk for Staatskonzern) and nicknamed the Feisar, was the primary assault rifle of the Terran Federal Republic from the mid 2300s until the introduction of the SCAR-773 in 2632. It was designed and manufactured by the Terran State Corporation until its dissolution in 2492, when manufacturing assets were transferred to TMP. Over the years, it went through several major iterations, initially made by TSC, and later by TMP and GA. The last model to be put in mass production was the M10, put into service in 2560. With all iterations and variants combined, over 100 billion FSRs have been built. It is still widely in use today, especially among criminals and insurgencies.
The name Feisar has emerged a term widely used to refer to hypervelocity assault rifles, starting in the late 2300s.