@ijasonalexander I appreciate you taking the time to express your thoughts in more than 140 characters. I disagree with your conclusions, but respect your tone, and share your distaste for any extremist rhetoric. Perhaps you will find it useful to hear some thoughts from someone who is willing to disagree with you respectfully.
1. At this point, we don't know which of the Aurora killer's weapons was/were used primarily. Maybe most of the wounds were inflicted by the Glock handgun he was carrying, rather than the rifle. If so, much of what you wrote is not pertinent to yesterday's events. But of course it is still relevant to discussion of possible future similar events.
2. Your constitutional point about the militia: It is certainly understandable why one would see the militia clause as having been intended to severely limit the scope of the right to bear arms. But that is probably not the correct or best understanding.
As you might guess, there is a truly massive academic literature on this very point, across law and history books and journals. But let me recommend just one article for you to read: "The Commonplace Second Amendment," from the NYU Law Review, by Eugene Volokh, a constitutional scholar at UCLA, available online here: http://www2.law.ucla.edu/volokh/common.htm
He explains from contemporaneous sources why the limiting interpretation is probably not correct. His article was approvingly cited by the US Supreme Court in 2008 in its landmark Heller case on the 2nd amendment. They shared his interpretive approach.
3. As others have probably pointed out to you, federal law does actually define the militia to include all able-bodied males ages 17-45. See http://en.wikipedia.org/wiki/Militia_(United_States)#The_reserve_militia.
4. Call me nutty, but I take seriously the possibility of degeneration of our democracy into tyranny. We've seen, e.g., Germany make such a descent in a frighteningly short period of time. Do I think it likely? No. But I do not dismiss it.
I'm not sure it's accurate to say that most of us sharing that concern think that an armed populace would "win" an all-out war against the military. I think more important is the simple consideration that an armed populace would make such a war so horrendously costly in lives and dollars that it is very unlikely ever to be attempted. I consider that a good thing.
5. You contrast the AR-15 with "sporting" rifles. This is a mistake. I do a lot of competitive shooting, and the ONLY use I have for an AR-15 is for such recreational competition--not for killing. I have never hunted, and never want to. We can disagree about whether my right to have fun in a contest of target shooting speed and accuracy is important enough to be worth the cost of occasional horrors such as yesterday's. But it is demonstrably false to say that these guns have NO purpose other than killing.
6. It is extremely difficult to define in legalistic detail how to differentiate something like an AR-15 from what you are likely envisioning as a standard hunting rifle. They are not as dissimilar as you may be thinking. Rifles come in nearly infinite variations of caliber, length, accessories, type of action, magazine capacity, etc. There are gradations, not sharp lines, between types. I don't expect you to have sufficient technical knowledge to actually attempt to write a law that would accomplish the kind of ban you seem to have in mind. But I do ask you to consider that it might be very, very difficult to make a legal distinction between the rifles you think are bad and those that you think are OK.
I have other lesser points of disagreement, but I'll not intrude further on your time. Thanks for reading.