Contemporary firearms identification and ballistic imaging techniques are predicated on the deposition of markings on evidence as a result of random variation in key processes—the manufacturing of firearms and ammunition parts and the mechanical operations and controlled explosions involved in the firing of a gun. The main objective of a national reference ballistic image database (RBID) is to use an image catalog of these markings to provide an investigative linkage between evidence collected at a crime scene and the original point of sale of the weapon. However, it may be useful to consider a completely alternative approach to arriving at the same goal: altering firearms so that, on every firing, they impart a known, unique, and unalterable marking on spent casings, rather than relying on the toolmarks generated by the firing process.
If such known markings—for instance, a gun-specific alphanumeric code—are logged at the point of sale, the same goal as a national image database would be achieved: a spent casing recovered at a later crime scene could be rapidly traced back to the point of sale by reading the etched marking. Likewise, known and individual markers could be placed directly on individual pieces of ammunition; again, if the component codes in a box of ammunition are logged at the point of sale, investigative leads could result later in time when pieces of stamped ammunition are found at crime scenes. The question is whether these alternatives compare favorably to a national RBID, in terms of cost, accuracy, or time savings.
This kind of technology—known as microstamping—has become a prominent part of the contemporary debate on “ballistic fingerprinting”