The M240 is the US designation for the FN MAG 58 and has been used by United States armed forces since the 1980's. As such, its parts are interchangeable with other weapons in the FN MAG family of machine guns. The weapon was originally intended for use as a mounted machine gun on tanks, but can be found mounted on various other vehicles or used with infantry. It replaced the M60, which was far less reliable, but the M60 is still used today. A version of the M240 optimized for ground combat, the M240B, comes with a buttstock and bipod. Surveys made amongst US soldiers on the M240B during missions in Afghanistan were positive, and while many complained that carrying the weapon and its ammo and setting it up was too difficult, 82% found it reliable. Its stopping power and bullet penetration were highly regarded. Many variations of the M240 exists, some intended for ground use, while others for vehicular or airborne use.