Unlawful

Check page 78 of the regs: (I bolded the pertinent part).
11. Prohibited firearms/hunting methodsIt is illegal to:
• Hunt game birds with a shotgun capable of holding more than three shells.
• Hunt game birds with a rifle or pistol, except forest grouse.
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Hunt game birds or game animals with anything other than a firearm, a bow and arrow, or by falconry. Bullfrogs may only be taken by angling, hand dip netting, gigging, and bow and arrow.
• Hunt game animals or game birds with a shotgun larger than 10 gauge.
• Hunt wildlife with a crossbow, except in firearm restriction areas during modern firearm seasons. Hunters with disabilities may also use a crossbow during any season that allows archery equipment with a special use permit as conditioned in WAC 232-12-054.
• Hunt wildlife with a fully automatic firearm.