No, Mr. Sullum, you have it wrong

Virginia's Thwarted 'Assault Firearm' Ban Illustrates the Folly of Trying to Distinguish Between Good and Evil Guns

The paradox is that this illustrates the need for a regulated militia, which is empowered to hold assault weapons. So take the requirement for a regulated militias, add to that th illegality of a government taking in the fourth and you get the complexity, easily resolved.  The regulated militia needs the private sector to manufacture and distribute assault weapons. 

I have the right to hire a regulated militia, with assault weapons, as defined by regulated militia. And we have private regulated militia, licensed by the second amendment to hunt down NRA nuts and extinguish them.  My right, guaranteed by the Second.

So, you see, the first part of the second is what I need to defend myself against NRA nuts, the second amendment gives me the right to hunt them down, drive them into the woods, out of sight of civilized people. We use the second amendment to shoot Walmart mass killers, we use it to kill off church shooting NRA nuts, we use the second amendment to hide snipers around the cabins of NRA nuts. We use it to defend against lunatic politicians like Rick Scott.

So identifying the good assault weapons is easy.  They are the weapons outside the door of NRA nuts, pointing at NRA nuts, ready to shoot NRA nuts; professional killers hired by normal folks to drive NRA nuts out of town. We are regulated and trained, as you can see from all the NRA nuts blowing their brains out as we surround them.