?So explain to me why you are doing this. Old black powder cartridges like .45 Colt, .38 Long Colt, and .45-70 had large cases (well, 2 out of 3 at least) because it took that much black powder to shoot a healthy round. Smokeless invention made black obsolete, and made cases smaller. Cowboy shooting brought back the old black powder guns, but because most of us shot smokeless, it meant that even if you shot a full-house .45 Colt, you didn't put much powder in that huge case (eg. 6.2 gr of Titegroup in a .45 Colt for max load - WAY less than the case took). Trail boss was designed to be a bulky powder to take up space. 5# of Trail Boss uses the same cans as the usual 8# of regular powder. So the cowboy shooters were finally given an option to load their cases fairly full yet still shoot something lighter than full house.

You are talking about weapons that were designed for smokeless. Part of whatever advantage you get from the calibre you choose is the case capacity. Yet you are shooting far less than the case capacity. ?Why not just shoot a smaller calibre. I'm just not following the reasoning here, other than "I can".