Ballistic fingerprinting is almost completely nonsense as used in media. Has some real life use, but limited.
There are multiple types.
1. Capturing a spent casing and comparing to a reference of that firearm. The idea being the primer indentation, and chamber wall tolerances/imperfections should let you match fired case to firearm. This was believed in so much that every firearm sold in the past 20 or so years in NY/MD/?? has required a spent case to be shipped with the gun and a case kept at some crime labs, or the owner is required to provide when registering the gun - the bullshit is that it doesn’t work at all - and not one single solved crime has ever been attributed to this
system. Giant waste of money / feel good legislation. There is some correlation to be made… Factory Glocks have fairly unique square firing pins and it’s easy to say a case was or wasn’t fired from an unmodified Glock. Likewise, MP5 platform guns typically have fluted chambers and one can easily see the case marks on a fired case, but neither of these things will help with storing a sample.
2. Muzzle/barrel printing. While this is a LITTLE more scientific, mostly shit. For the most part, you need a really large flaw in a barrel to leave a matchable print on the barrel. You can look a fired bullet and easily tell the rifling. Polygonal (Glocks again), cut, button, hammer forged… but the whole microscope printing of miniature and unique imperfections is a lot more art than science. Again, easy to prove this bullet didn’t / couldn’t come from this gun - but hard to prove it came from this specific gun.
3. Micro stamping entirely bullshit. This is where a California despite overwhelming evidence it doesn’t work is still trying to get firing pins to leave a unique impression on the primer. The people that push for this stuff have no idea how guns work, never have.
Lived in MD. They did away with the spent shell casing law. Turns out they were literally throwing them unorganized into barrels. No way to organize or search through them if there was a need. Just a massive waste of taxpayer money.
There are multiple types.
1. Capturing a spent casing and comparing to a reference of that firearm. The idea being the primer indentation, and chamber wall tolerances/imperfections should let you match fired case to firearm. This was believed in so much that every firearm sold in the past 20 or so years in NY/MD/?? has required a spent case to be shipped with the gun and a case kept at some crime labs, or the owner is required to provide when registering the gun - the bullshit is that it doesn’t work at all - and not one single solved crime has ever been attributed to this system. Giant waste of money / feel good legislation. There is some correlation to be made… Factory Glocks have fairly unique square firing pins and it’s easy to say a case was or wasn’t fired from an unmodified Glock. Likewise, MP5 platform guns typically have fluted chambers and one can easily see the case marks on a fired case, but neither of these things will help with storing a sample.
2. Muzzle/barrel printing. While this is a LITTLE more scientific, mostly shit. For the most part, you need a really large flaw in a barrel to leave a matchable print on the barrel. You can look a fired bullet and easily tell the rifling. Polygonal (Glocks again), cut, button, hammer forged… but the whole microscope printing of miniature and unique imperfections is a lot more art than science. Again, easy to prove this bullet didn’t / couldn’t come from this gun - but hard to prove it came from this specific gun.
3. Micro stamping entirely bullshit. This is where a California despite overwhelming evidence it doesn’t work is still trying to get firing pins to leave a unique impression on the primer. The people that push for this stuff have no idea how guns work, never have.