It should be noted that neither a real original Schofield or Russian, or #3 later breaktop will shoot many rounds of black powder before fouling to a stop. It, as well as the mixed ammo problem, was probably another reason the Army sold off the Schofields and retained the slower reloading, but far more black powder tolerant Colt SAA.
I have an original Smith 3rd Model in 44 Russian, and either black powder or Pyrodex will stop the gun before two full cylinders are fired.
However, the near alignment of the cylinder gap and the gas ring gap on the Uberti guns (and the S&W 2000) make the situation far worse. I don't understand why Uberti made their Russian cylinder so long, unless they had possibly planned to chamber 44Special.
The VTI website a few years ago carried 44 Special cylinders (and barrels?) for the Schofield, but Uberti never delivered the parts, so the part is no longer listed.
The Schofield cylinder is a bit longer than the Russian, but if Uberti had chambered 44 Schofield instead of 45Colt, they could have shortened that cylinder and extended the gas ring. I do realize that the rebirth of the Schofield round for CAS shooters came after the introduction of the Uberti gun.