[Dave T]

I just had to jump in here guys because I shot Cowboy Action for 9 years using black powder cartridges exclusively. I did a lot of research on the original loads for the 45 Colt and duplicated them (verified by chronograph).
The original 45 Colt loading was 40g of FFg behind a 255g bullet of 1-20 alloy. It produced 910 fps from a 7 1/2" barrel; 885 fps from a 5 1/2" barrel; and 860 fps from a 4 3/4" barrel. These were all first generation Colts just to keep things honest.
Cowboy loads are weak so the macho cowboys can win trophys and ribbons. Factory ammo is weak because most people don't like recoil.
The original 45 Colt was a serious weapon, with substantial kick on both ends, hense the nickname "Peacemaker".

PS: One of the several reasons I got out of Cowboy shooting was all the complaints about my loads being too heavy, too smoky, and too hard on the targets. And so it goes.