Tested various hardness boolits in the 454 Casull today. Shot 5-shot groups with boolits at 10.1, 11.0, 12.5, 14.3 and 15.4 Brinell. All loads were 300 grain Lee flat point GC boolit atop 25.0 grains of IMR-4227. Load was previously chronographed at approximately 1230 feet-per-second. All groups were 2 to 3 inches at 25 yards except the 12.5 Bhn that can be seen below . If it isn’t there then I haven’t figured out the picture posting portion of this forum yet. It printed all 5 in the same hole. Swabbed the bore between sets with no apparent leading.
A bit miffed about Lee’s Min/Max pressure table though. I would expect this load generates around 36,000 PSI which Lee’s table would require a hardness of 26.0 to 28.5.
Now I'm Addicted!