The M13 link, formally Link, M13, is the U.S. military designation for a disintegrating metallic link specifically designed for belt-fed firearms and rounds; it was introduced in the mid-20th century. It is the primary link type for the U.S., and among NATO for 7.62 mm ammunition. It has been in use for over 50 years as of 2007 and is used on the Dillon M134D Minigun, M60 Machine Gun, FN MAG, AA-52, HK21, and the MG3, among others.
The M13 link replaced the M1 links used on the older M1917 Browning machine gun and M1919 Browning machine gun family, though some conversions of the M1919 to the M13 were done, such as on the U.S. Navy Mark 21 Mod 0 machine gun, which saw service in the Vietnam War. Once converted it cannot use other link types, as firearms made for the M13 Link are not backward compatible with the M1 link (or other systems).
In West German service the link received the designation DM-13. Some other countries also redesignated it when it was adopted.