Wash. Rev. Code § 70.74.350
Small arms ammunition primers shall not be transported or stored except in the original shipping container approved by the federal department of transportation.
Truck or rail transportation of small arms ammunition primers shall be in accordance with the federal regulation of the United States department of transportation.
No more than twenty-five thousand small arms ammunition primers shall be transported in a private passenger vehicle: PROVIDED, That this requirement shall not apply to duly licensed dealers.
Quantities not to exceed ten thousand small arms ammunition primers may be stored in a residence.
Small arms ammunition primers shall be separate from flammable liquids, flammable solids, and oxidizing materials by a fire-resistant wall of one-hour rating or by a distance of twenty-five feet.
Not more than seven hundred fifty thousand small arms ammunition primers shall be stored in any one building except as next provided; no more than one hundred thousand shall be stored in any one pile, and piles shall be separated by at least fifteen feet.
Quantities of small arms ammunition primers in excess of seven hundred fifty thousand shall be stored in magazines in accordance with RCW 70.74.025.
RCW 70.74.350