I understand that kids out on some huge farms, with few other homes in sight/range can be relatively safe with guns of some types, but accidents always can happen to the best of us. A shotgun doesn't have that much range, but at close quarters it can probably destroy a door or make a wide hole through your tummy.
I believe that a pistol makes sense as home defence, but carrying one outwith the boundaries of your home looks like being a good reason for losing your licence, at least. As for guns that shoot multiple rounds in seconds, how on Earth can anyone not in a war justify possession? You wouldn't hunt with one, would you? Maybe some would - improve their chances against a deer or a wolf? Or how about a bear? Being quite big and bulky, one might actually hit it.
The news often shows pictures of guys wearing towels on their heads standing still and shooting up into the air. I have never seen one falling down due to his action. Maybe falling bullets burn out, just like a rocket on reentry. (Joke. Probably a feeble one.) Perhaps somebody falls down out of sight. I was going to say out of shot, but thought better of it.
How any law can remove the millions of guns already out there, I don't know; it probably can't. But, that would not imply that carrying those weapons around with you should not carry a severe punishment if you get caught, whether using it or not: possession could facilitate removal, of at least the ones so discovered, from off the streets. Not making any more for sale outwith military controls is a great start, if you think it matters whether folks get killed by guns or not.
There's a not so subtle difference between home defence and carrying weapons in public.
I'm sure nobody wants to stop people enjoying target practice etc. but hey, not in public where somebody else can get killed.
Rob