As merely a semi-informed opinion, I would have doubts about the potential accuracy of an old .45 Colt cylinder with a .45 ACP barrel. The reason being the older .45 Colt cylinders tended to have .456" or so chamber throats. The .45 ACP barrels tended to be more in the range of .452". IMO the reason my S&W 25-2 in .45 ACP works, in spite of a .456" chamber throat, is because the .45 ACP case is so small the large pistol primer blasts the bullet through the throat and across the barrel cylinder gap into the forcing cone before the power pressure has risen enough to cause trouble with blow-by. If the barrel is good, and the chambers have good alignment, you can get good accuracy, like my 25-2.
In .45 Colt, the case is large enough that the pressure of the primer is attenuated by the volume and powder charge. The bullet is moving from the primer discharge, but the powder burn catches up with it before it exits the cylinder. Blow-by of the hot gas around the base and sides of the bullet are often detrimental to accuracy. One way around this is to use a large, soft, preferably hollow base bullet that will open to throat diameter, then be swaged to bore diameter by the barrel forcing cone. That is typical of several factory .45 Colt loads. I just wouldn't try to hot rod it with flat base, hard cast bullets.
Or I could be totally wrong and it works great.
