Yeah, I did. Have Water's books and he gave the subject a pretty through treatment. That is probably where I made the AI capacity comparison from...or who knows.
Was pretty serious about building one but didn't...probably worried about the brass. Remember reading something like Swarf read about the most efficient 7mm, in terms of the ratio of velocity to powder. Interestingly Lyman #46 also said "compared to other magnums this cartridge produced very high velocity with minimum amounts of powder." Which really isn't all that much of a surprise due to the smaller case..:)
FWIW, Lyman #46 shows a max load of 67.5 H-4831 for the 139s...
There was an old boy from here in MI that wrote it up back then, too. I kinda wish I had--the 280AI feels kinda modern of of a sudden...
