Good point on the primers, I didn't consider that. My line of thought was building up some warmer 45 colt loads vs some low to mid range 454 loads for range use. It seems that one can get similar results from either cartridge from the same gun. Until one wants to exceed what the 45 colt can safely do, then it's time to use 454 cases and load data.
Excellent advice from this forum as usual. Thanks