Firearms Regulations.
Firearms and other weapons are subject to legal regulation.  Among other restrictions, the state prohibits all persons from manufacturing, owning, buying, selling, loaning, furnishing, transporting, possessing, or controlling any machine gun, bump-fire stock, undetectable firearm, and certain other weapons, subject to various exceptions.
 
Washington does not specifically define and regulate a general class of weapons designated as assault weapons, but the state has established various restrictions on a group of weapons classified as semiautomatic assault rifles.  State law defines a semiautomatic assault rifle as any rifle that utilizes a portion of the energy of a firing cartridge to extract the fired cartridge case and chamber the next round, and that requires a separate pull of the trigger to fire each cartridge, but this definition excludes antique firearms, any firearm that has been made permanently inoperable, and any firearm that is manually operated by bolt, pump, lever, or slide action.

Restrictions on semiautomatic assault rifles include:

• No dealer may deliver a semiautomatic assault rifle to the purchaser until:  (1) the purchaser provides proof they have completed a recognized firearm safety training program within the last five years; (2) the dealer is notified by the chief of police or sheriff that the purchaser is eligible to possess a firearm and the purchase is approved; and (3) 10 business days have elapsed since the purchase application or, in the case of a transfer, 10 business days have elapsed from the date a background check was initiated. 
• The purchaser of a semiautomatic assault rifle must be personally known to the dealer or present clear evidence of his or her identity. 
• A person under 21 years of age may not purchase a semiautomatic assault rifle, and no person may sell or transfer a semiautomatic assault rifle to a person under 21 years of age, subject to various excptions.

Federal law previously restricted certain semiautomatic assault weapons, subject to various exceptions and a sunset provision.  These federal restrictions expired in 2004.  Nine other states and the District of Columbia have enacted laws imposing various restrictions on assault weapons.

The Consumer Protection Act.
The Consumer Protection Act (CPA) prohibits unfair methods of competition, and unfair or deceptive acts or practices in trade or commerce.  If a person is injured in their business or property by a violation of the CPA, the person may bring a civil action to enjoin further violations and recover actual damages, costs, and reasonable attorney's fees.

Whenever the Attorney General believes any person may have material or information relevant to an investigation into a violation of the CPA, the Attorney General may issue a civil investigative demand requiring the person to produce the materials, permit inspection and copying, answer interrogatories, or testify.  Additionally, the Attorney General may bring a legal action to enjoin violations of the CPA, obtain restitution, and seek civil penalties.

The manufacture, importation, distribution, sale, or offer for sale of any assault weapon is prohibited, subject to limited exceptions.  

The term "assault weapon" is defined to include various kinds of firearms, including:

• a semiautomatic rifle that has an overall length of less than 30 inches;
• a semiautomatic centerfire rifle that has the capacity to accept a detachable magazine and has one or more additional features identified in the act;
• a semiautomatic centerfire rifle that has a fixed magazine with the capacity to accept more than 10 rounds;
• a semiautomatic pistol that has the capacity to accept a detachable magazine and has one or more additional features identified in the act;
• a semiautomatic shotguns that has one or more additional features identified in the act;
• any of the specific firearm models identified in the act; and
• a conversion kit, part, or combination of parts, from which an assault weapon can be assembled or from which a firearm can be converted into an assault weapon, if those parts are in the possession or under the control of the same person.

The term "assault weapon" excludes antique firearms, firearms that have been made permanently inoperable, and firearms that are manually operated by bolt, pump, lever, or slide action.

The term "import" excludes situations where an individual possesses a large capacity magazine or assault weapon when departing from, and returning to, Washington, so long as the individual is returning to Washington in possession of the same large capacity magazine or assault weapon the individual transported out of state.

The restrictions on assault weapons are subject to several exceptions:

• Licensed firearms manufacturers are authorized to manufacture, import, distribute, offer for sale, or sell assault weapons for the purpose of sale to the armed forces of the Untied States or Washington, or to any law enforcement agencies for law enforcement purposes, or to a person who does not reside in Washington.
• Licensed firearms dealers are authorized to import, distribute, offer for sale, or sell assault weapons for the purpose of sale to the armed forces of the United States or Washington, or to law enforcement agencies in Washington for law enforcement purposes.
• Licensed firearms dealers are authorized to distribute, offer for sale, or sell assault weapons that were acquired from an individual legally authorized to possess or transfer the weapon, for the purpose of selling or transferring the weapon to a person who does not reside in Washington.  This exception is subject to the limitation that its purpose is to allow individuals who no longer wish to own an assault weapon to sell their assault weapon, and it is not intended to allow dealers to purchase assault weapons wholesale for the purpose of selling a stock or inventory of assault weapons online or in person to nonresidents.
• Licensed firearms dealers are authorized to sell or transfer, out of state, the existing stock of assault weapons owned by the dealer that was acquired prior to January 1, 2023, for the limited period of 90 days after the act takes effect.
• Any person may inherit an assault weapon upon the death of the weapon's former owner, if that former owner was in legal possession of the weapon and the person who acquires possession can establish such provenance.  A person who inherits an assault weapon under this provision may not sell or transfer the weapon to any other person in Washington other than to a licensed dealer, to a federally licensed gunsmith for the purpose of service or repair, or to a law enforcement agency for the purpose of permanently relinquishing the assault weapon.

A violation of these restrictions is classified as a gross misdemeanor.  Additionally, a violation is classified as a matter vitally affecting the public interest, not reasonable in relation to the development and preservation of business, and an unfair or deceptive act in trade or commerce and an unfair method of competition for the purpose of applying the Consumer Protection Act.

If the Attorney General issues a civil investigative demand regarding a potential violation of these restrictions, the recipient of the demand may file in Superior Court a petition to extend the time to respond, or to modify or set aside the demand for good cause.  Additionally, the Attorney General is prohibited from sharing any materials or information obtained through a civil investigative demand with any law enforcement agency conducting a criminal investigation, unless required to do so pursuant to a search warrant.