he was looking for as much high pressure capability as possible.
Dick doesn't run anything on the low end.
he loads his 9mm with blue-dot a lot of blue-dot.
I got a double handfull of 454 Brass from him to turn into some 450 Express mag brass about 10-12 years back and it was all small primer.
the 450 is the fore runner to the 454, Dick built those pistols in a partnership with NAA [the guy's that make the tiny pocket pistols] but you could get them with all/any of the 3 chambering's,,, the 450, the 45 win mag., and the 45 colt.
the pistols themselves are a little hard to explain.
kind of a heavy Ruger single action Barrel/ on a heavy Dan Wesson frame, with a slightly over sized part 73' colt finished off as a Bisley grip would be close.
anyway the 450 brass is all large pistol/rifle it's basically a slightly long 45 colt length 45 win mag case.
I had to trim the 454 cases back to chamber length, then cut the rims down so they would chamber and headspace on the case mouth.
I ended up notching the cases above the turned off rim with a triangular file, a hacksaw blade, and a drill motor just enough to fit the shell holder.