The vote for Senate Bill 5992 on Thursday night came as a rare victory at the Washington Legislature for gun-regulation advocates.
For years, proposed gun laws in Olympia have stalled long before getting a full vote of the Legislature.
That inaction stands in stark contrast to the new gun laws Washington voters broadly approved at the ballot box in 2014 and 2016.
On Thursday, four Republicans joined Democrats to approve the bump-stock ban, including Sen. Dean Takko, D-Longview, who previously said he was leaning against the proposal.