That’s a really cool find, from a post I read online; “I don't have a lot of information on this line of shells. Here is what I do know. The name "Defiance" was registered on April 27, 1926 to the United States Cartridge Company and was renewed on April 27, 1946 to the Olin Industries (the company that absorbed US Cartridge Co.). 1942 is the latest that I can find any national advertisements for this line of shells.” (Information quoted from a guy named Doug, in the Friendly Metal Detecting Forum online)