Abstract: An indicia for marking on an object, such as a cartridge case, for representing selected information, such as identification indicia identifying the firearm that discharged the cartridge, and methods and apparatus for generating, imprinting and reading the identification indicia. An indicia includes a multi-dimensional array of encoded marks, including encoded marks determined by spectral encoding variables representing the selected information wherein each spectral variable is spectrally distinguishable from others of the spectral variables representing variables, and an encoded pattern of the encoded marks is determined by algorithmic transformation of the selected information. An indicia may also include hologram related artwork. An indicia may be an encoded hologram multi-dimensional barcode, an encoded hologram or an encoded concentric circular barcode and may be formed of a single indicia or as an array of indicia.

Abstract: A firearm comprising a gun barrel for accommodating a desired round of ammunition having a bullet, a shell casing and a primer. The gun barrel has a firing pin associated with a chamber of the gun barrel and the firing pin is activated by a trigger assembly. When the firing pin is activated by the trigger assembly, a striking surface of the firing pin strikes the primer and discharges the round of ammunition to propel the bullet out of the opposite end of the gun barrel. The firing pin, the interior surface of the barrel, or some other surface which contacts the shell casing carries a unique identifying indicia. Upon discharge of the round of ammunition, the component of the firearm carrying the unique identifying indicia transfers an impression of the unique identifying indicia to an exterior surface of the shell casing to identify that the shell casing was discharged by that firearm.