Michael, yes this is WA legal, a semi-auto shotgun can hold up to 7rds in the magazine, so you are good to go.
WA restrictions here budsgunshop.com/feeds/state_reg/washington_restrictions.pdf ,
Stay safe & have a great day!

Michael, yes sir this is perfectly legal in Washington. So you're good to go. Hope this helps.

Hi Michael and welcome to the community. Yes, shipping to WA State is no issue. Only detachable magazine semi-auto shotguns with features like pistol grips etc. are more restricted. Cheers and stay safe!