I'd prefer a cartridge with a powder volume that's the same or very close to a cartridge with accepted pressure data. I have no interest in going into unknown territory when it comes to load data.
I don't know if you're replying to me, but it sorta looks like it, so: That's exactly why I mentioned the Raptor - it is the same size and capacity as the 460 S&W (which is not a wildcat and has plenty of data), and uses the same load data. The difference is the lack of a rim.
Also in case you didn't know - you can make 460 S&W brass by shortening 444 Marlin, and 45 Raptor is basically a shortened 444 Rimless; these are all the same basic case, just with or without a rim.
I did make a typo though, it's the 45 Raptor, not 460 Raptor.
