Howdy
Thanks for the complement, but I don't claim to be this forum's, or any other forum's premier revolver expert. I just have a lot of revolvers.
Yes, I have a 7" (not 7') Schofield, and it shoots just fine with Black Powder. That's because it was made in 1875 with the original S&W design.
Yes, when Uberti reproduced the Schofield design, as well as the Russian Model and the New Model #3, in order to put a longer cylinder, for 45 Colt and 44-40, into the frame, without lengthening the frame, something had to give. That would be the bushing on the front of the cylinder. They did not actually completely do away with the bushing, but they did shorten it enough that it does not shield the cylinder arbor from fouling blasted out of the Barrel/Cylinder gap as well as the original, longer bushing did.
Here is a photo of a couple of cylinders. The one in front has the shortened bushing. To the rear is how long the bushing should be to properly shield the cylinder arbor from Black Powder fouling blasted out of the B/C gap.
To illustrate, here is the cylinder from my New Model #3. Notice how long the bushing is that is pressed into the front of the cylinder.
Here is the way it goes together. The ejector rod slides inside the arbor, while the bushing stays outside the arbor.
The bushing is approximately .160 proud of the face of the cylinder. That means the opening at the front of the bushing is approximately .160 horizontally removed from the B/C gap. That is enough to protect the arbor from most of the fouling blasted out of the B/C gap.
The smaller bushing on the front of modern Uberti reproduction #3 Top Break revolvers is not tall enough to effectively deflect fouling blasted out of the B/C gap away from the cylinder arbor.
Incidentally, I just put 50 rounds of Black Powder 44 Russian ammo through my NM#3 last weekend at a CAS match. It performed like a champ, except for the one round I put over a target, because I forgot to hold low. These things had very short front sights and tended to shoot high. Removing the cylinder I can see that a little bit of fouling did indeed make it onto the cylinder arbor. But owing in part to the helical clearance cut on the arbor, as well as using bullets lubed with plenty of BP compatible bullet lube, AND leaving a good coating of Ballistol on the arbor, it performed like a champ.