The effective range for revolvers in the .36 and .44 caliber configuration during the "war" was around 30 yards or so at most. That's hitting and killing range. Clint Eastwood riding along at breakneck speed with two Army Colts in his hands blazing away at "the enemy" was mostly Hollywood. You have to consider that back then most pistol ammo was round ball. Manufactured cartridges that used elongated lead projectiles were actually less accurate as they were difficult to seat in the chamber using the ram on the pistol. You seem to be a shooter so you know how important it is to get a bullet inserted straight into it's case or in this situation, the chamber. Lighter powder loads are more effective for accuracy due to their predictability. Hot loads do strange things to bullets. Trajectories get really screwed up when you are trying to force an already unstable and un-aerodynamic object down a controlled path (and in addition adding a spin to it). My favorite target pistol is a modern Dan Wesson .357 Magnum with a six inch barrel, open sights (scopes are for rifles). The most consistently accurate round for this weapon is not the .357 magnum but the .38 special. Hand loaded 38s will always outperform the magnum in shear accuracy. This is because the lower powder charge will give more consistent results. Of course the added power of the magnum round will kill better but with the added power comes more recoil, more noise, more erratic flight, and less "black paper". If you want to get some cool results with that Walker, cut back on the powder, keep the weapon clean and try to be consistent with your shooting style and technique. No matter what the caliber or what the load, if you can't hit it, it won't go down. Guns are fun. I grew up with them. Too bad they get such a bad rap today. Have fun and keep shooting cap and ball. We live history.
P.S. Elmer Keith invented the modern .44 magnum round from a .44 special case that was lengthened to accomodate more powder. This man has confirmed deer kills with a Smith and Wesson Model 29 with a six inch barrel and open sights at over 400 yards. Now this guy new his pistol and it's cartridge. He would have to be good with a M79 grenade launcher. you think? BLOOOP.