I don't support "illegal gun" crackdowns, often touted by politicians and the UN. First, "illegal guns" shouldn't be illegal in the first place, but strict libertarianism aside, Norton has it right. The huge issue is what defines an "illegal gun", and this can be changed quite easily.
Kind of like illegal immigrants, eh?
Illegal guns are guns in the hands of prohibited persons, gotten there outside of legal production and distribution channels. I don't have a problem with cracking down on that.