ATF proposes to define "sex" on firearms and explosives forms as immutable biological classification

Proposes to amend 27 CFR 478.21, 479.21, and 555.21 to specify that "sex" as used on ATF forms means "an individual's immutable biological classification as either male or female" and excludes gender identity; to require applicants to select their biological sex; and to conform perjury language across the three parts. The forms affected include the Firearms Transaction Record (Form 4473) used at every federally licensed dealer sale, National Firearms Act transfer applications, and federal explosives licenses and permits. Because Form 4473 is executed under penalty of perjury and is the basis for NICS background-check identity matching, the definition operates on transgender purchasers whose identity documents bear a different designation. Unlike the other CFR terminology actions, this one proceeds by notice and comment. ATF cites E.O. 14168; the preamble does not discuss transgender applicants.