A baseball bat could be as deadly as the person holding it wants it to be. So could a kitchen knife. So could a car. So could a shoelace. Obviously it's not practical to ban ownership of certain objects just because they could potentially be deadly. But there's a question of efficiency - we can't legislate out the risk of mass murder from our society, but shouldn't we at least take measures to make it more difficult to achieve? To extend the analogy, why are explosives illegal to own? So it's OK to be able to mail-order the necessary equipment to kill 30 people, but not 50?
And yes, I would advocate limiting civilian non-handguns to single-shot rifles and shotguns. If you're worried about not having enough time to load if you didn't kill the bear on the first shot, you can either learn how to be a better shot, take measures to avoid the risk of being eaten, or accept the risk. I would strongly consider limiting handgun ownership to two per household or one per adult. Why does anyone need to amass an armory in his basement? What purpose does it serve? We don't need a militia anymore - times have changed. We're probably not going to see eye-to-eye on this, because this is one of those rare times that I can make a blanket statement that I'm positive I will never reconsider - nobody will ever be able to give me a compelling reason why a civilian would need an automatic rifle.