No, because a bump stock isn't a firearm. I'd be okay with holding gun sellers or producers economically culpable for unlawful deaths due to the use of a product they sold. I would because part of the fully cost of unlawful gun use is the loss of life and ability stemming from it. That cost should be borne by producers and sellers and in turn passed on to buyers. Now., sure as I've written the remarks above, I realize that the viability of such a proposal depends on the price elasticity/inelasticity for guns, and I don't know what it is.