See the problem with that is there's really too much of a gray area... and we all know those are the worst things you can have in laws and policies. You can't say like " you can have weapons that spray things but you can't have ones that shock people "
It's just ridiculous.
Which is a reason why weapons should be allowed. Semi and automatic weapons shouldn't be allowed, along with the obvious (nukes, Agent Orange, pipe bombs), but handguns should be allowed.
The crime rate would have a great chance to decrease. Think who would want to rob a bank of there is a chance that the cashier in the corner has a fully loaded shotgun in their desk.