So I was sick today... recovered by taking the 454 BC carbine to the range. Tried several 45LC and 454 loads with 2400 and 4227, all with 250gr and 300gr XTPs. Not good. Get a couple close, then fliers...
So I fired one last group with 4227 behind some lead bullets I got as an extra in a trade; what I think is a .454 360gr LBT (Cast Performance?) GC bullet. 4" higher than the jacketed, but all 5 touched.
That's when I remembered this barrel doesn't like .452.
Must be old age...