The law is muddled over where to draw the line between the kind of arms protected by the Second Amendment and those outside it. There is one Supreme Court case which approved a ban on sawed off shotguns, but the reasoning was specious. A purely military weapon like a shoulder-fired rocket, which is a cross between artillery and a rifle, is well outside anyone's interpretation of the Second Amendment. But that fact alone doesn't mean the government can draw the line anywhere it wants. The Supreme Court made it pretty clear in the DC decision that they cannot outlaw ordinary conventional handguns or the like.
The issue of whether or not high cap mags or "assault rifles" are protected under the Second Amendment has not been definitively answered, although it is being litigated. It is very possible the Supreme Court coudl rule they were protected. The Second Amendment talks about militias, not "legitimate sporting and hunting purposes." A militiaman needs an infantry weapon, ie an assault rifle, not a single shot squirrel gun. And he needs an effective handgun, the kind police departments use, ie a high capacity, big calibre, semi-auto.
