GSR can be used to both determine if a person was shot at close range, but also if someone was holding a gun when it was fired. The earlier link had linked to an article that said .22s wouldn't leave residue on the hand of the shooter because they were rim shot cartridges. It showed a picture of an exterior percussion cap from a higher caliber that had been punctured and stated that it was primarily the percussion charge elements that were looked for to find GSR that blows back to the hand when the cartridge is fired and since .22 cartridges were rim shots that was why GSR wasn't an effective test for .22s. It could be that I misread some of that article as well, I skimmed it pretty fast.
But yeah, that surprised me, because I'd think the elements found in the smoke residue leaving the barrel would also be rarely found in the environment and that quite a bit of that, no matter what caliber you used, would leave some residue on the firer's hand.
But yeah, that surprised me, because I'd think the elements found in the smoke residue leaving the barrel would also be rarely found in the environment and that quite a bit of that, no matter what caliber you used, would leave some residue on the firer's hand.