Court Rules 2nd Amendment Gun Rights Apply to 18-21 Year Olds History First In 2018 Voters of Washington State approved Initiative Measure No. I- 1639 which resulted in several changes to existing laws including denying the right for anyone under 21 years of age to legally purchase and possess a handgun. An article in the UK Guardian described the State's voting picture as, "I-1639 passed on a roughly 60-40 split; in the big, blue counties west of the Cascade Mountains, such as King County, where Seattle is located, the margins were even bigger....However, 27 of Washington's 39 counties rejected the ballot measure. Many of those counties are in the state’s more rural, sparsely populated districts."