We have to make the laws that are reasonable to our time. The Constitution allowed slavery, for instance, and no vote for women.
Yeah, and when times changed it got amended. But the right to bear arms hasn't been amended, and until it does, it still stands as the law of the land that all arms are included.
Does it make sense now for individuals to buy and sell full-auto weapons? "Assault rifles"? Flamethrowers? Surface-to-air missles?
Absolutely! How else is the public supposed to support a revolt against tyranny? (That is what the 2nd Amendment is for, you know... it's a rule written by violent revolutionaries for violent revolutionaries.)