It looks like this is likely to pass. It prohibits the importation of specified guns, and prohibits transfer to anyone in WA other than by inheritance.
https://lawfilesext.leg.wa.gov/bienn...20230329164907
I thought I'd mention one thing people might not have noticed: the bill bans semi-auto pistols with threaded barrels. If you have been thinking about getting a threaded barrel, or a pistol that only comes with a threaded barrel like the Sig 322, you might want to look into it.
The bill takes effect immediately when signed.
(IANAL. Replacement barrels aren't specifically mentioned. My guess is that putting a new threaded barrel into an existing gun, or for that matter cutting threads on an existing gun, or putting an SBX barrel on your 10/22 might be considered to be manufacturing an illegal gun. But IANAL)