A friend made this claim over the weekend. I asked him for some information regarding how this is so, and he couldn’t give me a satisfactory answer. Is this the case?
This is right out of one of those “topics sure to be locked down” threads. 
Not sure what the official meaning of “traceable” is, but unjacketed bullets are less likely to survive an impact with well defined rifling marks than copper jacketed bullets. .22 bullets typically are plain lead, or very lightly plated (really just cosmetic)
OTOH, the low velocity of a .22 makes it more likely to survive intact.
Considering .22’s are rimfire, wouldn’t that make it more difficult to match the casing with the gun?
Why do you say that? There is always a firing pin mark which be used to match toolmarks from a gun.
THespos sometimes bullets cannot be matched with the gun they came from. Even under good circumstances it isn’t as easy as TV police make it seem but saying that .22 bullets are untraceable is absolutely false.
To prove the statement true you’d have to show that .22 bullets can’t be recovered intact or that they don’t retain marks from the barrel & its rifling. Neither of these is plausible.
Are you sure you don’t mean muzzle energy? A typical .22 cartridge has a higher velocity than most other size rounds but a much lower muzzle energy.
I believe bullet expansion and deformation is strongly correlated to velocity, not energy.
I’m not sure if I can allow this here. I’m closing this thread.
-xash
General Questions Moderator