The Switchblade Act, (Pub.L. 85-623, 72 Stat. 562, enacted on August 12, 1958, and codified in 15 U.S.C. ? 1241?1245), prohibits possession on Federal lands, Indian reservations, military bases, District of Columbia, Puerto Rico and other protectorates. It prohibits manufacture and sale of switchblades in interstate commerce. The act was amended in 1986 to also restrict ballistic knives. Federal law controls Federal aspects only, and does not mandate prohibition within an individual state. It does say specified knives can not be mailed through the U.S.Postal Service, and provides penalty exceptions for other common carriers/shipping companies doing normal business.
18 U.S.C. ? 1716(g)(2) provides this summary:
Federal law prohibits shipment of automatic knives across state lines, with the following exceptions: Switchblade knives can be shipped: (1) to civilian or Armed Forces supply or procurement officers and employees of the Federal Government ordering, procuring, or purchasing such knives in connection with the activities of the Federal Government; (2) to supply or procurement officers of the National Guard, the Air National guard, or militia of a state, territory or the District of Columbia ordering, procuring, or purchasing such knives in the connection with the activities of such organization; (3) to supply or procurement officers or employees of the municipal government of the District of Columbia or the government of any State or Territory, or any county, city or other political subdivision of a State or Territory; procuring or purchasing such knives in connection with the activities of such government. (4) to manufacturers of such knives or bona fide dealers therein in connection with any shipment made pursuant of an order from any person designated in paragraphs (1), (2), and (3).
15 U.S.C. ? 1244 provides, in summary: Knives can be shipped by common carrier, that sale, transportation or distribution, possession or introduction into interstate commerce of switchblade knives is authorized if it is pursuant to a contract with the armed forces or any member or employee thereof acting in the performance of his or her duty may possess switchblade knives and may have them shipped to him and sold to him or her. The possession and transportation upon his or her person of a switchblade knife or a blade 3 inches or less is authorized to any handicap individual who has the use of only one arm.