Firearms Firearms and Toolmark Identification. Firearms and toolmark identification involves more than just guns. Also included in this broad subject area are explosives, imprint evidence and toolmark evidence.
Most physical evidence concerns itself with class characteristics and individual characteristics.
Class characteristics are those characteristics which are common to a group of similar objects. For example, you buy a pair of Air Jordan sneakers. All Air Jordan sneakers have to same shape and same tread design on the bottom. These are class characteristics. Individual characteristics are those characteristics which are unique to a given object and set it apart from similar objects.