"This invention relates to a method and system for marking the inner surface of the barrel of a firearm with an identifying indicia for transfer to a bullet passing therethrough, reading the indicia from the bullet and identifying the firearm and, in particular, to the modification of the inner surface of a firearm barrel using a laser for the purpose of producing one or more areas of permanent grooves, which impart firearm data onto rounds passing through the barrel in contact with the inner surface of the barrel to form a barcode-like pattern which may be read by a barcode scanner and matched to the firearm."