Those two things, geen'yoos.
And again, making something illegal to own (Not slap on the wrist you don't have a permit illegal. You're violating a convention of war by being an illegitimate combatant by holding on to this, illegal.) Is not, ever, going to stop people from getting it, whatever it is. You probably won't see jimmy cruising around in his Gaz Willies with a CIWS gun bolted into it every day. But Mr. and Ms. Doe (or Mr. UCAS) live in a bad neighborhood and understand that regular 9mm's aren't going to save their lives in a pinch, but they know the top shelf magnum load +P rounds that are forbidden that go in their registered guns WILL. People, criminal or otherwise, will get what they believe they need, outlawing it makes it so that NOW the item in question is being produced by underground sources and isn't traceable with nice RFID tags and being filed under their SIN. So now, you think that everyone is being good with their gun licenses and collecting pistols, completely unaware that that collectors item is actually in Ms. Doe's purse and loaded.