Washington prohibits any person from manufacturing, owning, buying, selling, loaning, furnishing, transporting, or having in his or her possession or under his or her control any: 1) machine gun; or, 2) any part designed and intended solely and exclusively for use in a machine gun.1 It is also unlawful to convert a weapon into a machine gun, or to assemble or repair any machine gun.2 However, it is an affirmative defense to a prosecution brought under this section that the machine gun, was acquired prior to July 1, 1994, and is possessed in compliance with federal law.3 Federal law generally allows private citizens to possess machine guns manufactured prior to May 19, 1986 so long as they are registered.
In Washington, all machine guns, or any part designed and intended solely and exclusively for use in a machine gun, to convert a weapon into a machine gun are declared to be contraband, and all peace officers and members of the armed forces are required to seize machine guns or machine gun parts.4
The state also prohibits any person, in the commission or furtherance of a felony, to discharge, menace or threaten another person with a machine gun.5
In 2018 Washington prohibited any person from manufacturing, owning, buying, selling, loaning, furnishing, transporting, or having in his or her possession or under his or her control “bump-fire stocks.”6 Bump-fire stocks, also known simply as bump stocks, are a type of firearm accessory that can significantly increase its rate of fire to function similarly to a machine gun. In October, 2017, a shooter used multiple bump stock devices in an attack on concert-goers in Las Vegas to perpetrate the deadliest mass shooting attack in modern history. Washington defines a “bump-fire stock” as “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 energy from the recoil of the firearm to generate a reciprocating action that facilitates repeated activation of the trigger.”7
See our Machine Guns policy summary for a comprehensive discussion of this issue.