The SIG MCX is a family of selective fire guns designed and manufactured by SIG Sauer. The civilian legal models are available in semi-auto only. SIG designed the upper receiver to be compatible with standard AR-15 and M16 lower receivers with the help of an adapter.
This tag applies to all the prominent variants, such the original SIG MCX assault rifle, the second generation SIG MCX Virtus, the short-barrelled SIG MCX Rattler, and the multi-caliber SIG MCX Spear (that can be 7.62mm NATO battle rifle).
