Post
by mundaire » Sat Sep 08, 2007 4:24 pm
Shotgun and other spent cartridge casings can be traced back to a particular gun BUT this is NEVER 100% accurate. Unlike fingerprints and other biometric measurements such markings have a substantially higher chance of having identical "twins".
What can be done, and what these markings are usually used for is to tie in a suspected gun with a crime. IIRC there were proposals in some countries to maintain "ballistic databases" of all firearms, however the idea was dropped due to the fact that mining such databases on a countrywide basis would end up giving the police several false positives and entail their wasting time on these red herrings, besides the harassment and invasion of privacy of many innocent gun owners - also the cost involved in creating and maintaining such a database would be huge. All guns would need to be tested once, and then again at regular intervals - BECAUSE unlike human biometric measurements, ballistic fingerprints of all guns keep changing, with use, age, repairs etc. not to mention if someone switches a major part like a barrel, firing pin, ejector etc.... THEREFORE keep in mind the term "ballistic fingerprint" is itself a bit of a misnomer....
In terms of the projectiles - ONLY RIFLED guns (pistols, rifles, etc.) produce identifiable and repeatable ballistic fingerprints on projectiles fired from them. Smooth bore guns (a.k.a shotguns) DO not produce such marks on the pellets fired through them, simply because they have no rifling in their barrels which is required to produce a unique (well almost unique) fingerprint on a projectile/ projectiles fired through them...
I guess paradox shotguns firing paradox slugs may be an exception, since they do have rifling at the end part of their barrels, but since paradox shotguns are not exactly dime a dozen, I very much doubt that one of them would have been involved in this particular incident. Also, a 12 gauge slug would hardly be the cartridge of choice with which to poach such small sized game... and if all the person was using was birdshot, then they would not be identifiable/ traceable back to a particular shotgun.
What the authorities could have established in terms of circumstantial evidence would seem to be -
a) He had a shotgun AND dead animals/ birds in his possession
b) The cause of death of the animals/ birds was due to gunshot wounds
c) The gun(s) found in his possession had been recently fired
d) He had powder residue on his hands - strongly suggesting that it was indeed him who had recently fired the gun(s) in question
e) Spent shells found in his possession could be traced back to having been (strong likelihood but NOT with certainty, unless seen together with other evidence as mentioned above) fired the guns in his possession
f) HOWEVER, IF HE HAD USED A .22 rifle (a common choice for such escapades) - then they could indeed have traced back the projectile(s) recovered from the carcasses back to the rifle in his possession - this with a good deal of certainty BUT NOT 100% certainty.
It seems to me from the Journos specific reference to the word "rifle" and also the fact that a .22 LR bullet is small enough to seem almost "pellet like" that this may indeed be the case here...
Just keep in mind, even where possible ballistic fingerprinting is NOT 100% accurate...
Cheers!
Abhijeet
E & OE
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