Bruce,
There's a chapter on 9.3 Barsness-Sisk in THE BIG BOOK OF GUN GACK.
Charlie has the reamer, and building one is mostly a matter simply rebarreling any action made for any of the short, fat, beltless magnums, whether WSM's, SAUM's, or RCM's.
Shooters still sometimes ask why we used the .350 Remington case, when the WSM case has more capacity. There were three reasons:
1) Charlie noticed the .350 often fed even better in WSM/SAUM actions than the WSM/SAUM rounds.
2) We didn't want more case capacity. Instead, we wanted to duplicate the performance of the 9.3x62 in a short action, and the .350 case has just about the same amount of powder room. It worked out exactly like we planned.
3) We chose a belted magnum case to make sure brass for conversion would always be easily available. This proved to be pretty smart. Even .300 WSM brass is sometimes in short supply.
