27 CFR § 72.21 - Personal property and carriers subject to seizure.
(a) Personal property may be seized by duly authorized ATF officers for forfeiture to the United States when involved, used, or intended to be used, in violation of the laws of the United States which ATF officers are empowered to enforce, including Title 18 U.S.C. Chapters 40 (explosives), 44 (firearms), 59 (liquor traffic), 114 (contraband cigarettes), 229 (liquor); Title 26 U.S.C. Chapters 51 (distilled spirits), 52 (tobacco), 53 (firearms); and Title 27 U.S.C. 206 (liquor). Carriers, as defined in § 72.11, similarly may be seized when used in violation of Title 49 U.S.C. App., Chapter 11 (transportation, et cetera) of contraband firearms or contraband cigarettes.
(b) Any action or proceeding for the forfeiture of firearms or ammunition seized under 18 U.S.C. Chapter 44 shall be commenced within 120 days of such seizure.
(c) Upon acquittal of the owner or possessor, or the dismissal of the criminal charges against such person other than upon motion of the Government prior to trial, or lapse of or court termination of the restraining order to which such person is subject, firearms or ammunition seized or relinquished under 18 U.S.C. Chapter 44 shall be returned forthwith to the owner or possessor or to a person delegated by the owner or possessor unless the return of the firearms or ammunition would place the owner or possessor or his delegate in violation of law.