Howdy
Your bushing is probably stuck from corrosion over the years.
I had this tool made up by a friend with a lathe a bunch of years ago. It is specifically for removing stuck bushings from Colts (or Ubertis, since the dimensions are quite similar). I think I got the dimensions out of Jerry Kuhnhausen's book
The Colt Single Action Revolvers, A Shop Manual.
The tool is brass, so it will not damage any of the steel parts. Colt (and Uberti) cylinder pins are nominally .250 in diameter, so the front end of the tool, the part that fits inside the rear of the bushing, is .245 in diameter. The larger diameter, which fits inside the ratchet teeth at the rear of the cylinder is .330 in diameter. The narrow part is .750 long, the wide part is 2.250 long.
Sorry, I don't have a photo of it in action, but with the cylinder removed from the revolver, you run the narrow part up into the bushing and the square shoulder of the wide part will sit on the rear of the bushing and clear the ratchet teeth by about .010 all around. Inserting the narrow part of the tool all the way into the bushing keeps it aligned and prevents it from contacting the ratchet teeth. You don't want to be whacking on something that may not stay in alignment.
This old Colt Bisley had a stuck bushing, and this tool was just the ticket to get it out. A few gentle taps on the rear of the tool with a brass hammer, and the bushing came free. You may notice that the cylinder pin has been chewed up a bit at the front, probably by Bubba trying to pull it out with a pliers. A little polishing of the outside of the bushing and it slips in and out just like it was supposed to when this Colt left the factory in 1909.
i saw somewhere else that putting the base pin in the loading side and tapping on it has worked and i tried that but it didnt move at all so i dont know if tapping on a brass punch would get the job done
I have no idea how that should work because the stock pins that come with a Uberti are simple cylindrical pins. There would be nothing for the pin to bear against to remove a stuck bushing.
The other thing to try is to run some penetrating liquid down between the bushing and the cylinder. I recommend Kroil. You can apply some to the front of the bushing, but the larger diameter head of the bushing will probably prevent it from penetrating very far. The rear end will probably allow better penetration. Try both ends, and let the assembly sit over night so the penetrating fluid can work.
Do not despair if you cannot remove the bushing. One of my 2nd Gen Colts has a bushing that no amount of urging has been able to remove, and I have tried everything. Finally, I just decided to let it stay stuck. It has been like that for the twenty years I have owned the gun and everything is fine.
The idea behind the removable bushing is it would be a sacrificial part that would take the wear generated as it rotated around the cylinder base pin and inside the cylinder. Much simpler to replace the bushing than replace the cylinder. Ideally, the bushing is a slip fit, easily removed with no tools. This was reasonably important in Black Powder days, when fouling might gum up the works. Pretty much a non-issue today with Smokeless powder. For what it's worth, my 2nd Gen Colt with the stuck bushing works just fine with Black Powder, as do my Vaqueros which have no separate bushing at all.
By the way, there is no such thing as a 4th Generation Colt. When the 3rd Generation first came out, the bushing was pressed in place and was not meant to be removed. But because so many complained about the non-removable bushing, at some point Colt put a removable bushing back in, and shooters started calling that the 4th Generation. But collectors will tell you there is no such thing as a 4th Generation.
