I shoot Classic Cowboy with my 45s, so I want to keep the load as light as possible. I'm using 5.6 of TrailBoss behind a 200 gr RNFP and I'm getting good accuracy with both my pistols ( Ruger OMV - 5.5 in. barrel) and with my rifles (1860 Henry). The rifle gets some blow by, but unless you are going with heavier loads in the 45 Colt (and, according to some, heavier bullets), blow by and dirty cases are a fact of life with 45s. I just tumble the cases in the lovely Lyman Green corn cob for a couple of hours and the dirty cases are just a memory...