Prohibits a person from manufacturing, owning, buying, selling, loaning, furnishing, transporting, or having in possession or under control, a bump-fire stock.

Provides the following definition for bump-fire stock: A butt stock designed to be attached to a semiautomatic firearm with the effect of increasing the rate of fire achievable with the semiautomatic firearm to that of a fully automatic firearm by using the energy from the recoil of the firearm to generate reciprocating action that facilitates repeated activation of the trigger.

Requires the Washington state patrol to establish and administer a bump-fire stock buy-back program which allows a person in possession of a bump-fire stock to relinquish it to the Washington state patrol or a participating local law enforcement agency in exchange for a monetary payment of one hundred fifty dollars.

Provides a January 1, 2020, expiration date for the buy-back program.