I believe the USA-F markings are components of a contract with the U S Army. The Department of Defense (DOD) uses a thirteen alpha-numeric system to convey certain information. Position 9 identifies the type of contract. For example, capital A is a blanket purchase order, D is an Indefinite Delivery contract, F describes contracts w/or through other Government Depts., or agencies, (more words), etc., and P is a Purchase order-automated. So, I believe the capital letter F is one of several alpha letters that describes the type of instrument mentioned in the contract.

The U S Army part of USA-F abbreviation is identified in the first six digits of a DOD contract. The 6 positions IDs a department/agency and offices issuing the contract. The DOD uses an activity address code (DoDAAC) that uniquely IDs a unit. activity, or organization that has the authority to requisition, contract for, receive, have custody of, issue, or ship government-owned assets or fund/pay bills for materials and/or services. The U S Army would be one of those organizations.

In summary, the contract ID system used in the 1940 era, looks like, in some respects, to the one used currently. This is a 80 year leap, granted. Also, I hope we can eventually get more information from the Library of Congress that will shed light on the Rochester Ordnance Arsenal/L C Smith shotguns.

Best regards. Roger