Gun Analysis Essay

In starting I will begin with firearms and their examination and identification first. Forensic examination of firearms was established in the United States and Europe during the early years of the Twentieth century. Most places firearms examiners are also involved in tool mark ID, residue from the guns, and serial number identification. Firearm analysis is the study and identification of bullets, spent cartridges, and how unique each firearm and bullet is. There are many types of firearms an examiner may be around including some homemade ones. Pistols are smaller guns intended to be fired with one hand and this includes revolvers. Semiautomatic guns use the gas pressure and some springs to eject the fired cartridge, load a new one, and ready

When a cartridge goes through these lands and grooves it gives spin to the bullet, which gives the trajectory and increases accuracy over smooth bore weapons. This creates distinctive striation in what can be called patterns which can match gun and bullet later on. The striations are usually unique to one gun based on the way the gun is manufactured and used. To machine lands and grooves into a barrel, different tools can be used, all of which involve metal-to-metal contact. Although a tool is used to cut many barrels, each barrel that is machined will cause wear on the tool, creating small irregularities and random wear patterns that can be transferred to the next barrel machined. This next barrel will also create irregularities and so on, meaning that the markings on each new barrel cut will be slightly different and thus unique. In addition, once a gun is purchased, it will have a different usage pattern from every other gun and thus a unique wear pattern on the lands and grooves. Thus, slight differences created during milling combined with individualized wear patterns lead to a unique striation pattern for most guns. As a result, the marks each gun imprints on bullets and cartridge cases should be unique or very nearly so. These imprints are a kind of impression evidence, as are tool marks. For this reason, many firearms examiners are also responsible for the analysis of tool mark