The Schofield is slightly smaller case volume than a .45 Colt, so I would expect that any powder that is satisfactory for the Colt (at regular SAAMI pressure limits) would also be adaptable to the Schofield (but at smaller charges for the same bullet weight).
That said, I think that unburned powder is a common issue with smokeless powder loads in the .45 Colt at SAAMI pressures.
Trailboss powder was designed for just this application, so, if you want a powder that will nearly fill the case, burn well, and not exceed SAAMI pressure standards, that is what I would recommend.
On the other hand, if you don't mind a tiny amount of powder sloshing around in those big cases, then "Clays" (NOT "Universal Clays"), W-231, or Bullseye are fast powders that will probably give you less unburned powder at max SAAMI pressures.
I don't know what the manufacturer of your gun recommends as the maximum pressure for loads in THAT MODEL, but if there is some room between the SAAMI pressure limit for the Schofield and your gun's pressure limit, you could get cleaner burning by going to a somewhat higher pressure.
That is a common practice for Rugers in .45 Colt, where the SAAMI limit is only 14,000 psi, but the "Convertable" cylinders for the same guns shoot .45 ACP ammo with a SAAMI pressure limit of 21,000 psi or even 23,000 psi for the +P 45 ACP ammo. Jacking the .45 Colt up to the same pressure levels as the .45 ACP gives much better powder burn as well as much better velocity/performance. But, not all Colt SAA clones are capable of withstanding those pressures. (On the other hand, some of the Ruger models that are made on the large frames are loaded as high as 32,000 psi, which competes well in performance with the .44 Magnum cartridge with the same weitght bullets.)
But, you need some good, reliable information about the strength of YOUR gun model BEFORE trying higher pressure loads.
And, you then need to make sure that any loads that exceed SAAMI pressure limits are clearly marked as such and NEVER get into another gun.
Last edited by SL1; December 9, 2012 at 08:03 AM.