Okay, I'll bite.
How about guns that are commonly used to hunt?
How about guns that allow a homeowner to defend his life and property against intruders?
How about guns that allow store keepers to defend against robbery?
How about guns that can protect couriers from attack?
How about guns that gun enthusiasts can compete with?
Does anyone really need a semi? A well-regulated militia used to use single load, single shot rifles. To say that, in this modern world, a single load gun is no longer sufficient to defend us from foreign assault is also to say that tanks, bazookas, rpgs, grenades, ICBMs, nuclear bombs, and fully automatic weapons are now required to defend our country by ordinary citizens. This country was adamantly opposed to a standing army in those days. That is why the Constitution wanted the populous to be armed, and ready to defend the country. But, we now have an armed, standing military force, the likes of which this world has never seen before. If you want to defend the rights of ordinary people to extraordinary modern weaponry, then you must be in favor of replacing our military with a nuclear equipped 'Billy Bob'.