I'm sure someone else has thought of this but darned if I can find it.
In the never ending search for more power, I took a few 444 Marlin cases, fireformed them in the BFR so they would accept 250 gr .45 bullets. The first round was light but I should be able to work up past 454 velocities at a much lower pressure.
Peter, you're having way too much fun.
;D