В целом статья о проблемах с национальной системой идентифицирования оружия, сколько это стоит, как часто помогает и т.д.
Меня заинтересовала следуящая выдержка оттуда:
"Ballistic imaging has obvious limitations that become more significant when we consider image databases containing all guns, or all new guns, rather than only criminal guns. Even when limited to new guns, the usefulness of an immense database as a crime fighting tool is questionable for a number of reasons.
"Wear caused by the friction of bullets traveling down a gun's barrel will change its 'signature.'"
Identical Marks. Initially, all guns of the same model from the same manufacturer will produce similar marks; guns produced by the very same equipment (perhaps only minutes apart) will be especially similar.19 This means that even the best search algorithm will develop relatively long lists of "possible" guns that need to be test fired so the bullets and cartridge cases can be microscopically compared to the evidence.
Worn Barrels. Over time, wear caused by the friction of bullets traveling down a gun's barrel will change the barrel's "signature," producing different ballistic images for bullets fired when the gun was new and those fired later.20
A barrel's ballistic signature often changes much more rapidly when the barrel is new; after use, the barrel stabilizes. Sometimes the five-thousandth bullet fired through a gun will match the first; at other times, consecutively fired bullets will not match.21 This is especially true for firearms that are used with high-powered magnum ammunition. Maryland and New York currently require the collection of ballistic images from new guns. The images from these guns may be significantly different from the images produced once the gun stabilizes.
Inexpensive guns, which are made from softer metals, wear more quickly. How often a gun is cleaned also affects the rate of change of the ballistic images.22"