Just how pray tell, did they manage that? Invidiual rounds traced back to a customer or a fired projectile traced back to the firearm from which it was discharged?
Cheers,
Hi Biggles
It went something like this from a forensic perspective. Some cartridges were found at the scene and they had propellent residue left in them. The propellant has a 'signature' of how it was mixed together, like a cake. No two are the same though they may be very very similar, almost identical.
Some propellent was found in the suspects boot. It was examined and found to be consistent with a certain brand of ammunition.
The two are compared and found to be the same. This links the propellent at the scene to the offenders vehicle. From there I think they worked out the batch number for the cartridges and linked the offender to the purchase.
It went something like that (keep in mind this was 20yrs ago
and I am not a scientific bloke by any stretch )
Similar to when bombs go off. The investigators try to find residue to link it back to the offender.
In a more practical sense if Kevin shoots Julia and then ditches the weapon provided the cops can find a cartridge with some residue at the scene (or off the body/clothes etc) they can link the residue with the brand and batch of cartridges and who bought them.
If you look at the winchester investigation they couldnt find the weapon that fired the shot (a ruger). So they set about accounting for every single one ever sold and proved that the missing one could be the only one that fired the shot.
Anyways, I can see some benefit to law enforcement but think its a bit of overkill. The easiest thing would be that prior to a rifle being sold to the firearms dealer that its test fired and the fired round is digitally scanned and stored on disc. Then, if a cartridge is found at a crime scene they scan it and look for a match.
Whoever bought the gun from the dealer is the first point of contact with the plods.
Simple, cost efficient and no annoyance to the public. And lets face it, the vast majority of shootings are by people that know each other, normally family or ex friends, so its pretty easy to find em.
cheers