Gun owners there are on borrowed time, at this point. Washington State has a fairly iron-clad preemption law, but that didn’t prevent the Washington Supreme Court from upholding Seattle’s gun and ammunition tax. You can find the full opinion here.
One wonders how much Seattle could get away with taxing guns. $50 per gun? $100 per gun? A dollar per round of ammo? It wasn’t even close. Only a single justice argued that Washington’s preemption statute forbids any ordinance touching on firearms at all, which it clearly says.