II 115th CONGRESS 2d Session S. 2475 IN THE SENATE OF THE UNITED STATES February 28, 2018 Mr. Flake (for himself, Mr. Heinrich , and Ms. Cortez Masto ) introduced the following bill; which was read twice and referred to the Committee on Finance A BILL To amend title 18, United States Code, to prohibit the illegal modification of firearms, and for other purposes.