Firearm microstamping and micromarking insert for stamping a firearm identification code and serial number into cartridge shell casings and projectiles

A method for imprinting a unique identifying indicia onto a shell casing upon discharge of a firearm, wherein the firearm includes a gun barrel, a chamber coaxially extensive with the gun barrel for accommodating a round of ammunition including a bullet, a shell casing containing a propellant and a primer and wherein the chamber has a firing pin associated therewith that is activated by a trigger assembly to strike the primer and ignite the propellant to discharge the bullet from the firearm, the method comprising the steps of;

• locating a unique identifying indicia on an exterior surface of the shell casing, wherein
• the identifying indicia is formed on an inner surface of the chamber and in proximity to an outer cylindrical surface of the shell casing in the chamber, wherein
• the identifying indicia is formed on a base surface recessed from the inner surface of the chamber in a radially outwards direction, and
• an exposed surface of the identifying indicia formed on the base surface of the radially inner end of the indicia insert forms a cylindrical surface coincident with and substantially flush with the inner surface of the chamber, so that
• an identifying mark corresponding to the identifying indicia is imprinted on the outer cylindrical surface of the shell casing when the shell casing expands upon discharge of the round of ammunition by the firearm.

In a firearm having a chamber for accommodating a round of ammunition including a shell casing containing a propellant, a shell casing marking mechanism, comprising:

• a unique identifying indicia for imprinting a corresponding identifying mark on an exterior surface of the shell casing when the shell casing expands upon discharge of the propellant, wherein
• the identifying indicia is formed on an inner surface of the chamber with the identifying indicia being located in proximity to an outer cylindrical surface of the shell casing in the chamber, wherein
• the identifying indicia includes a base surface bearing at least one indicia feature, wherein
• the base surface is recessed from the inner surface of the chamber in a radially outwards direction, and wherein
• an exposed surface of the identifying indicia formed a cylindrical surface coincident with and substantially flush with the inner surface of the chamber, so that
• the outer surface of the shell expends outward in region adjacent the recessed base surface and against the at least one indicia feature due to gas pressure from the propellant when the propellant is ignited.

A firearm comprising:

• a gun barrel;
• a chamber, for accommodating a round of ammunition, extending coaxially with the gun barrel;
• the chamber having a cylindrical inner surface defining a chamber bore for closely receiving a shell casing of a round of ammunition;
• the chamber having a radial bore extending substantially normal to the chamber bore which receives an insert, and a radially inner most surface of the insert defining a unique identifying indicia for transferring a corresponding identifying impression, of the unique identifying indicia, to an exterior surface of a shell casing upon expansion thereof during discharge of a round of ammunition;
• and
• the radially inner most surface of the insert, defining the unique identifying indicia, being coincident with and substantially flush with the cylindrical inner surface defining the chamber bore.