Let's see how fast that "common sense" lasts after a major civilizational upheaval ... an EMP event, a nuclear exchange, a large-scale natural disaster, etc. We had a little foretaste of that over the past two years. It can get a whole lot worse.
Besides, if the second amendment protects anything, it protects the right of the people to arm themselves as the unorganized militia. That's not for deer hunting.
Absolutely you would.. and in fact, a 30 round magazine is far too small. You should go for 60 round magazines.