Drug violence is the result of drug prohibition. Just as alcohol violence was the result of alcohol prohibition (as proven by the fact that the violence ceased once alcohol prohibition was ended.)
Gun prohibition is (would be) just as effective as is (was) drug (alcohol) prohibition at reducing illegal use of the prohibited item/substance: It would be totally ineffective. But it would be at least as effective at engendering even more/worse violence.
Except they wouldn’t end firearm prohibition.