The common notion that faster powders will work better in shorter rifle barrels is wrong, primarily because all the powder that's going to turn into gas does so inside the first few inches of a barrel. (Muzzle flash is not unburned powder kernels flying out of the muzzle, but hot powder gas re-igniting when it hits the oxygen of the atmosphere.)
The same powders that get the highest velocity in longer rifle barrels get the highest velocity in short barrels too. If you want some proof, look at various loading manuals that list the same cartridge data in both rifles and handguns. You'll find the same powders getting the top velocities in both, or at least powders in the same burning rate range--slow
for the cartridge and bullet.
The least amount of velocity loss in a shorter barrel is typically with heavier bullets and slow powders.
