When a gun is fired and the bullet blasts down the barrel, it encounters ridges and grooves that cause it to spin, increasing the accuracy of the shot. This stamps an impression on the bullet and cartridge case. These markings are unique and like "ballistic fingerprints" that can be used to identify a gun.
Criminalist Scott Hoopes explains the science of firearms analysis and how matching the ammunition to a weapon provides vital facts in an investigation.
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Learn more about the San Diego Sheriff's Department Regional Crime Lab
sdsheriff.net/crimelab.html.
