I'm sorry, was there a question in your post? What exactly are you looking for from us?
Here's my 2 cents: I think the whole sporting purpose thing is bad law/policy. The 2nd Amendment has NOTHING to do with sporting purposes. The reason the 2nd Amendment exists is because the founders believed the government could not be trusted and they wanted to assure the people always had a way to resist. Based on that understanding (and on MIller), it is precisely evil black rifles (and shotguns) that should have constitutional protection. It stands to reason then that the ONLY acceptable conclusion of the ATF "study" should be that all sporting purpose BS should be tossed out as unconstitutional. Anything short of that is contrary to the intent of the founders and inconsistent with Supreme Court precedent.
Short of that, at the very least, Saigas and other evil and/or military-style shotguns should meet the UNCONSTITUTIONAL "sporting purposes" standard because of the fact that thousands upon thousands of Americans compete in sports that use these sorts of weapons. They are most certainly sporting guns. But agan, the whole sporting purposes BS needs to go away NOW.