Loopholes in Ballistic Fingerprinting

[pintler]

As mentioned, 'ballistic fingerprinting' - having a preexisting database of all guns and matching recovered brass to that database - presents some daunting problems.

Matching a recovered bullet to a suspected barrel is quite a bit more reliable, although not foolproof (e.g. two new barrels that were produced consecutively *may* have quite similar toolmarks).

Crooks trying to cover their tracks should be careful, e.g. a Glock 17 (9mm) has a 1 in 9.84 twist, while a Glock 31 (.357) has a 1 in 15.98 twist. A careful examiner would pick up on that, I'd think. Commercial bullets are also different, e.g. Speer 357 sig 125 gr is #4360, while a 9mm 124 grain is #3998. Aside from the one grain difference, the 357 bullet may be constructed differently, because of the higher velocity.

 

[1911Jeeper]

My gun is full of Ice bullets. Once the dude is dead, the ice melts, leaving no traces. Just in case the micro-stamping wasn't eliminated by the Dremel, the stolen gun I used to off the dude is at the bottom of the Mississippi river.

Seriously, the Government can't keep track of criminals, or prevent crimes by criminals, when their mugshots and their fingerprints are on file, how are they going to keep track of millions upon millions of guns ?

 

[scythefwd]

I know someone who has a screw on ballistics changer. It is literally a barrel extension of about 3-4 inches that is rifled. It imparts a second set of rifling marks on the bullet. 22 lr. You could fire all you want and test the bullets all you want on the primary barrel and see that it has a threaded tip... but who would ever expect a barrel extension with mismatched rifling on it to be used instead of something like a silencer.

 

[Jenrick]

We only catch the dumb ones. The odds of finding a particular random gun and being able to link it to any particular bullet are mind boggaling. What's much more likely is good suspect is developed, and a weapon located as an additional piece of evidence. I can't imagine a case being made on just a ballistics or tool mark match.

Besides the bullet is the least useful piece of evidence, you can get from a shooting. There's a lot of other physical evidence that goes along with a firearm being discharged that are much more valuable.

-Jenrick

 

[LibraPMC]

With all that said, does that mean police can use ballistic check as an evidence on a suspect only if they recovered their gun and test fires it? Then if one is not on a suspect list and even if they are, simple swap to aftermarket parts will defeat the test result... Wow reality is different!