In the spirit of rugged individualism
the firearm industry/culture ought to be free and clear of any economic impact on the rest of society. After all, freeeeeeeeedom, amirite? Elsewise they might owe someone, or trample of *another's* rights. No macho freedom loving patriot would do that.
Ergo, gun and ammunition makers, sellers, buyers/owners (in some combo together) ought to compensate the entire economic externalities of gun existence/usage. Any economist will tell you externalities distort the market. Of course. It is only fair, after all, to recognize their making all this money inflicts costs upon others and to compensate thusly, but it's fine, fine, fine b/c they make so much money they can cover it and still make profits. Happy, happy, joy, joy, everyone.
How exactly they do that I don't particularly care. Obviously all guns must be registered/recorded/tracked in order to collect the resources (not taxes nor fees, per se, just.... remediation resource collection) to redress these externalities. How else would you be sure nobody is free-riding? Any economist will tell you free-riding distorts the market. Of course.
And the precise cost of gun usage/violence/maiming/deaths must be tracked (including all manner of affiliated trauma, disability, etc., etc.) to determine to what degree the industry/owners must compensate society writ large for the externalities of their business/right-exercising. An arbitrary level of remediation resource collection won't do; if the number is set too high or too low, any economist will tell you that it would distort the market. Of course.
So you see, the invisible hand will solve everything, even gun violence.... so long as we arrange for these freedom loving patriots pay their just and fair share of externalities.