Scalia's reasoning in Heller was:
1. The right to keep and bear arms is an individual right, guaranteed by the Second Amendment.
2. The right protects the possession and use of firearms that are commonly owned for lawful purposes.
3. Handguns are a class of firearms commonly owned for lawful purposes.
4. A ban on all handguns therefore infringes the protected right.
You can substitute AR15 for handgun and get the same result. The AWB is dead, stiff, and stinkin'.
The Supreme Court will not revisit Heller and McDonald. They are settled law. Only in very glaringly wrong cases will the Supreme Court reverse itself. For example, the Slaughter-House case is very widely regarded as having been wrongly decided, but it will probably never be revisited. Some sitting Justices have opined that Roe v. Wade was wrongly decided too, but it won't be revisited either.
Scalia wrote an outstandingly good opinion. You can find a lot of people who don't like it, but it's hard to find people who can show that he was wrong.
It will take another couple of decades of litigation for the full effects of Heller and McDonald to be seen. By the time it all unfolds, I expect that the worst of our gun laws will go away. Things like the Illinois FOID will be just bad memories, but form 4473 will live on.
Do not underestimate the importance of these two decisions.