I am one of those people who believe a barrel can never be too long but they can be too short. I like long and heavy barrels and have the slings to carry them. After spending a decade or so diving with twin 72 scuba tanks, everything seems light.Normally the slower powders that give you the highest velocity in a longer barrel will give the highest velocity in a short barrel. The only difference is the short barrels will have more muzzle blast.
Look in the Lyman reloading manual at rifle loads and then look at the same loads for the Contender pistol. You will see what powders provide the highest velocities. I have a 16 inch barrel on my Winchester 94 Trapper model and a 20 inch barrel on my .308 Savage. And the slower powders still give you the highest velocity.
That being said you can download any cartridge using a faster burning powder to practice with. "BUT" you will reach max pressure at lower velocities than with slower powders.