Let me clarify something. I'm not proposing such a thing and, in fact, would vehemently oppose it as I oppose ANY tax to compel behavior modification because I think the loss of freedom isn't worth the results.
However, such cigarette-like taxes on guns has been proposed, and I guarantee you WILL be offered up sooner rather than later.
The whole purpose of this thread isn't to offer up a new plan for gun control, but to highlight that once you support the notion that taxes are a legitimate tool to compel behavior modification for smokers, you've already lost the battle to keep it being done to gun owners. The justification will be the same: Public safety. And, you've already bought off on that.
Sucking the combustion byproducts of the tobacco plant into your lungs is not a consitutionally protected right, and thus is susceptable to all sorts of laws, even an outright ban if someone decided along the way to do it.
Since smoking is not a right, methods such as onerous taxes to prevent such use, while not something I prefer, are not barred by the consitution.
Placing a tax on firearms for the sole purpose of making them too expensive to own by some people meets the definintion of "infringment" to me, and thus should be struck down as consitutional.
Something like this also raises the issue that the rich and well off (or well connected) would have easier access to firearms than someone not as rich, well of, or well connected.