I am really hesitant about posting this question - but, here goes. I just picked up a Ruger LCR 9mm. It came with three moon-clips. Getting it reminded me that Federal loaded a 9mm rimmed round many years ago. Just for kicks and giggles, I've done a little bit of Oogling and can't find a source for the brass. No surprise there. I've also looked at my SAAMI specs PDF and the only thing sorta-kinda close, case-wise, I can find is .38 S&W.
It looks like .38 S&W cases could be safely fire-formed (after trimming) in a 9mm revolver. 9mm P cases, should be .391 in front of the extractor groove - SAAMI says .38 S&W should be .386 - so 5-thousands difference. If I were to try that - I would fire-form them in my Ruger Blackhawk and use very mild loads. The problem, though, is that the .38 S&W rims may be too large to work in the LCR 9mm. And, even worse, there might be some serious head space issues due to the thick rims on .38 S&W. I'm just wondering if anyone else out there has ever thought about this or tried it?
This is just a mental exercise right now, which is very difficult for me ...
. I have the time to trim down case length on some cases to get them to work - but I don't have the tools, patience, or skill-set to attempt to turn down case heads. I just thought I'd mention this - maybe there is an easier way to to it. It would be nice to use the LCR without moonclips and it would give me a project to work on to keep me out of the bars...
Edited to add: I got started in the whole case-forming business years ago by using 9X21 brass to form and load .30 Luger. I had found, and subsequently sold, a .30 Luger Hi-Power barrel and wanted to form cases for it. I still have a Ruger P-89 Conv in .30/9mm + a Walther P5 with both barrels...