Washington

Restrictions Based on Convictions: Yes.

Documentation or Licensing: Not required

Where to Purchase: Can be purchased from dealers, retailers, or online suppliers.

Official Government Source:

Note:

The state has laws in place regarding the wearing of body armor(considered as armaments) while on campuses or other university controlled properties.

  1. Only such persons who are authorized to carry firearms, ammunition, or other weapons or armaments as duly appointed and commissioned law enforcement officers in the state of Washington, commissioned by agencies of the United States government, or authorized by contract with the university, shall possess firearms or other weapons or armaments issued for their possession by their respective law enforcement agencies or employers while on the campus or other university-controlled property, including, but not limited to, residence halls.
  2. Other than the law enforcement officers or other individuals referenced in the previous section, individuals seeking to bring a firearm or other weapon onto campus, university-owned property, or a university sponsored event must obtain prior written authorization at the university public safety department, which shall have sole authority to review and approve any such request and, if approval is granted, establish conditions to the firearm or weapon authorization.

To read more, look at the Washington state legislature.