The M13 link, formally Link, Cartridge, Metallic Belt, 7.62mm, M13, is the U.S. military designation for a metallic disintegrating link specifically designed for ammunition belt-fed firearms and 7.62×51mm NATO rounds. It was introduced in the mid-20th century. It is the primary link type for the United States and among NATO for the 7.62×51mm NATO cartridge. , it has been in use for over 60 years and is used on the Dillon M134D Minigun, M60 Machine Gun, FN MAG/M240, Mk 48, MG3, HK21, MG5, UKM-2000, K12, SS-77 and Negev NG-7, among others. Some countries redesignated the M13 link when it was adopted. History The M13 link replaced the older M1 links designed for .30-06 Springfield ammunition, which bound cartridges to each other at the neck, 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). The M9 link is technically very similar to the M1 link but designed for 12.7×99mm NATO/.50 BMG ammunition used in heavy machine guns like the M2 machine gun. The M1 and M9 links are pull-out designs. Rounds are extracted by pulling them rearward out of the link. The NATO Standardization Agreement STANAG 2329 Links for Disintegrating Belts for Use with NATO 7.62mm Cartridges described the M13 link in 1982. STANAG 2329 has been rendered inactive. The DEF STAN 13-33 - Standard NATO 7.62 Millimetre Rounds and Associated Chargers and Links is a 1982 standard by the Ministry of Defence of the United Kingdom. This Defence Standard specifies 7.62 mm small arms ammunition and its associated chargers and links for use by the Ministry of Defence to meet its commitment to NATO in the United Kingdom. The United States Army MIL-DTL-45403E (3) CONT. DIST. - Link, Cartridge, Metallic Belt, 7.62 Millimeter - M13 2021 specification covers the requirements and verification methods for the Link, Cartridge, Metallic Belt, 7.62mm - M13 for use in 7.62mm machine guns. Design details The M13 link is a push-through design. Rounds are extracted by pushing them forward out of the link. The left side of a single link has a semi-circular loop which