TTI used to make it and it was great brass.
Jamison had some issues with early lots. You can tell by the headstamp if it was the early lots (wouldn't stand very many reloads) or the later reloads. Probably be able to find this info using search, Fiftydriver is very knowledgable re: the 408 brass, as many of his wildcat's are based on it.
There was a European firm that made some brass as well, but I think it is impossible to find now. User "Black Diamond 408" uses this brass I think.
HTH,
AJ