The wrong way to argue against bans against them:
Gun control at its root has always been about gun control. Feinstein is a statist, and her laws and regulations will always and forever increase the power of the state. Feinstein sees through McArdle’s argument on cosmetics, which is why her proposed ban includes semi-automatic weapons. There isn’t anything cosmetic about the aims of the gun control advocates.
Arguing that their bans don’t adequately distinguish between weapons leads them to refine their ban. Arguing that there is equivalent lethality between weapons denies aspects of utility and design, and only causes them to ban weapons that have specific utility for home and self defense. And arguing that their regulations were ineffective only embarrasses them to pass even more onerous ones.
The correct way to argue against Feinstein’s proposed assault weapons ban is to argue that there is no constitutional basis for such a ban, and any new assault weapons ban would be at least as immoral and obscene as the last one was.
[Update a couple minutes later]
Related: Go have a Tea Party by seeing Red Dawn.