The law they were overturning was in fact an absolute prohibition of handguns but they were in no way saying that the line was drawn just on the other side of total prohibitions of handguns.
There is a bunch of stuff they don’t address and I think it is very optimistic of you to think that everything they don’t mention is going to fall your way.
Everyone is waiting for them to enunciate a standard of review (probably some form of intermediate review).
I don’t think it would be too hard to make mercury fulminate, as long as you can secure a supply of mercury. You would already need nitric acid for the smokeless powder.
I’m going on what they did say, not what they didn’t. It seems to me that there was no reason to include all of the dicta as to what laws were not touched by the ruling but to signal how narrow the ruling was intended to be. This isn’t something I came up with myself; there was plenty of commentary along these lines when the decision came down.
Certainly, I might be wrong; this is just an educated guess (and never stated with the certainty or the breadth of your re-characterizations of my remark ;)). And what I think the law will be and I might want the law to be are two separate questions, i.e., you can’t deduce an ‘ought’ from an ‘is’. 
OK now try putting that into a primer cap without blowing off your fingers.
Its a lot harder than simply reloading a bullet and powder into a cartridge. Its also a lot harder than making smokeless gun powder. Its just harder all around.
I was objecting to the notion that the case said “anything short of an outright ban is alright”
At some point the court is going to have to set a standard of review for the second amendment and no matter where they set it, there will be things short of outright bans that will be unconstitutional. If the standard of review is some form of intermediate scrutiny (the most likely scenario), then there will be MANY things short of outright bans that will be unconstitutional.
Really? *Although we do not undertake an
exhaustive historical analysis today of the full scope of the
Second Amendment, nothing in our opinion should be
taken to cast doubt on longstanding prohibitions on the
possession of firearms by felons and the mentally ill, or
laws forbidding the carrying of firearms in sensitive places
such as schools and government buildings, or laws imposing
conditions and qualifications on the commercial sale of arms.26
We also recognize another important limitation on the
right to keep and carry arms. Miller said, as we have
explained, that the sorts of weapons protected were those
“in common use at the time.” 307 U. S., at 179. We think
that limitation is fairly supported by the historical tradition
of prohibiting the carrying of “dangerous and unusual
weapons.”
I dont see anything about the back-door banning of firearms by banning ammo.