Individual characteristics

Individual characteristics are generally considered to be exceptional characteristics that may establish the uniqueness of an object and support the conclusion that the object in question can be linked to a known object (i.e., both the questioned and known object originated from a common source). For example, marks on various parts of a firearm that come into contact with the bullet/cartridge case may create individual characteristics that are produced by the random imperfections or irregularities on the surfaces of those parts. These individual characteristics are produced incidental to manufacture and/or caused by wear, corrosion, or damage. They are considered to be unique to that tool, but they are not always visualized in sufficient quantity on fired bullets/cartridges.