There should be info about that FBI load available on line in abundance. I may have read specific info in Handloader magazine. I can't recall for sure
Also there's an article penned by a writer named Skeeter Skelton and published by his wife after his death titled "My Friend the 357." It has some good info about heavy loads in 38spl cases. The data should be compared to modern data in recently published manuals for verification of safety, but the information is still good, even though it was written a long time ago.
Best of luck with your project.
I've read his article. Great reading and info.
