So I have an Uberti Dragoon 3rd model. Not realizing there was a gunsmithing section I posted in the Darksider Den regarding tuning it as that was where the tuning articles are. Coffinmaker has been very kind to answer my questions in that thread. I just want to get some clarification on this subject. Once you set the arbor fit if you have excessive endshake your only remedy seems to be removal of material from the frame/barrel connection where the 2 alignment pins are? Is this the gist of it?
As I posted in my original thread, " Looking at how this pistol functions it seems that the only thing indexing the cylinder is the bolt. With the hammer down the bolt fully engages the cylinder notch and the cylinder is "locked" in place. Like this I have exactly .015 with the wedge in. I cannot move the cylinder easily by hand it is locked. At half cock the bolt is retracted and at this point I can move the cylinder back and forth and the cylinder can be pushed forward and closes the gap. At full cock the cylinder is locked by the bolt as it is with the hammer fully down. Holding the pistol level and watching the cylinder as I pull the hammer to full cock and then slowly easing the hammer down while holding the trigger back the hand does not move the cylinder against the barrel the gap remains the same .015". As far as the hammer contacting the nipples it appears that the hammer stops exactly as it comes into contact with the surface of the nipple. With the hammer fully down if I force the cylinder forward overriding the bolt the hammer does not budge so it is not resting on the nipple. Looking carefully at the nipple/hammer contact there is no visible gap so I have to conclude that the hammer face is stopping exactly at the surface of the nipple. So should I take .005" off the button I installed to close the cylinder barrel gap to .010"? Or is something else going on?" Coffinmaker replied that if the arbor fit is correct leave it alone and just shoot it. However I am concerned that the .015 gap will lead to damage due to long term hammering of the parts due to recoil. So my question is leave it as is? Take .005 off the button which will cause a bit of a tilt issue but will reduce the gap? Why is my hand not pushing the cylinder forward as it is supposed to? Better to take .010 off the frame and my button to close end gap and keep everything parallel? Or put a lid on my OCD and do as Coffinmaker says and just shoot the thing?
I am familiar with Coffinmaker's instructions. Logically and mechanically speaking I would agree with your first suggestion in having to remove material from the frame/barrel connection with the same amount removed from the Arbor Button to maintain the same alignment, assuming parallel alignment to begin with. I do not know how you would determine or measure barrel alignment outside of how it appears visually. You don't want binding of of the arbor. Removing .005" from only the arbor button may be just fine if no binding occurs and alignment if fine as well but I'm not the one to say it should be OK.
The question is: Is that the way or the only way to reduce clearance (gap)? I do not know but what I do know, I can't see how. I'm no expert. 45 Dragon (Mike) is the one to ask. Mike is currently working on my 1872 Open Top which I found to have more of a gap than I think it should have and of course, mine is a cartridge gun, not a C and B and like yours, the arbor is short. The wedge was pounded in hard and even then the gap was .012". What you have suggested as a fix is exactly what I thought need to be done as well. It is logical. Mike is giving me the whole tuning package while attempting to close the CB gap. How he does that.... I'm leaving it entirely up to him. He's the expert.
From what I've learned, the Arbor fit is the single most important fit and it appears you have accomplished that. As for the .015" clearance.... If Coffinmaker says it's fine to shoot if the arbor is correct, I would believe him. Hammer to nipple clearance like a headspace clearance specification, I know nothing about what it should be but I can't believe that the hammer should make any kind of direct contact with the nipple. Sounds like you've determined that.