The M1 Gun Sling was made of canvas web. Some canvas web slings have the same MRT marking as the M1907 sling as well as a month and year date stamp on the metal tip, such as 4 64. The last USGI canvas web slings were made about 1966. It was known as the M1 Gun Sling and weighed 0.3 pounds or about 5 ounces. Subsequent slings, known as Small Arms Sling, have a different National Stock Number and are made of nylon weave material. The hard nylon weave sling was introduced in 1969. The first soft nylon weave sling was produced for the U. S. Navy about 1973.