Because it is of no use, the bloods and crips aren't going down to the local gander moutain to stock up on guns and ammo. How exactly is going to reduce crime, or lead to arrests if criminals get their guns and ammo via illegal channels? All it does is infringe upon the privacy of law abiding citizen.
ok - I see where you're coming from
just give up and do nothing
I don't buy the privacy argument.
why should the government know what car I drive?
Criminals most likely steal their cars anyway so all it does is infringe on my right to privacy