[Koblenz]

I'm not a gun nut, and don't even own any guns at the moment. (I also live in a densely populated suburb, Greenwich, CT, where most murders are done with golf clubs by Kennedy cousins, but I digress). Anyway, how hard is it to change the "fingerprint" of a barrel. Could you do it with a coat hanger? just ham it down the barrel to make new striations? Or would it require more?

[and the horse you rode in on]

how hard is it to change the "fingerprint" of a barrel. Could you do it with a coat hanger? just ham it down the barrel to make new striations? Or would it require more?

That's not gonna do it. It is like getting some scars on your finger. It does not destroy the underlieing fingerprint. Wear will remove markings eventually.

Try a bore brush wrapped with a patch and coated with valve grinding compound. Then follow up with finer compounds to polish out the scratches.

[mushroom]

It would take a little more than a coat hanger but not much. A simple rat tooth file down the barrel a few times, hit the firing pin with some emery paper, and run that file around the extractor and no one would ever be able to trace it.

An even easier way would be to fire a few cases of shells through it. After all, you need to practice regularly anyway.