There are good reasons for having firearms, including what might seem like high capacity magazines to folks who aren't familiar with these reasons (think: Joe Biden!). (By the way, 300 round magazines do not, in my opinion, have any place in the civilian world.) There are places I sometime have to go where exposure to feral hogs is probable. If you don't have a sidearm backup with you loaded with 15 and a magazine with another 15 nearby you're a fool. Those who've ever encountered one of these vicious beasts knows why. I also sometimes have to go places where criminal elements make it likely that I'll be in the presence of a stone cold killer mentality who has not yet victimized. I don't intend to be the first victim, and if I am I don't intend to stand there reasoning with a person who's confronting me or mine with lethal intent. He or she's going to get whatever I can give them right now and center-mass.
I believe in responsible civilian gun ownership. It would not hurt my feelings one bit for the US to require citizens to have a locally issued license to purchase, own and carry a firearm. This way non-criminals who feel the need have a means of purchasing, owning and carrying a firearm, and there is some minimum standard in place to demonstrate competency similar to what is done for driving an automobile on public thruways.