Citation(s) from the GunPolicy.org literature library
USA. 2007 ‘Marking of All SALW at Time of Manufacture.’ National Report of the United States of America on its Implementation of the United Nations Programme of Action to Prevent, Combat and Eradicate the Illicit Trade in Small Arms and Light Weapons in All Its Aspects (UNPoA), p. 2. New York, NY: Permanent Mission of the United States to the United Nations. 17 July
Marking of All SALW at Time of Manufacture
Since the 2001 UN Conference on SALW, ATF has established specific height (1/16th inch) and depth (0.003 inch) marking requirements for licensees who import or manufacture firearms.
[SALW = small arms and light weapons]