Cylinder Swapping and a Timing (?) Issue

[Cholla Hill Tirador]

 I got a 2003 production Uberti Flat Top 44-40 recently with the intention of "converting" it to .44 Special. I've done this very thing successfully with a '90's production Uberti and a that was really involved was getting the cylinder bushing worked down to the right length after which the new cylinder dropped in and now functions flawlessly. This one however is a bit of a challenge.

  Being the impatient type, I thought I'd try one of the .44 Special cylinders out of my current revolvers. No dice. I figured out that due to a slight difference in the teeth of the Flat Tops cylinder and my Special cylinders, the hand was engaging the Special cylinders before the bolt dropped. I happened to have a couple of spare hands so began shortening one incrementally until the bolt dropped when it was suppose to. (Let me take a moment to say I now officially HATE the plunger type hand spring...three tiny pieces begging to be dropped or otherwise lost each time they are removed prior to removing the hand!) So now the bolt drops when it should, but the hand won't fully rotate the cylinder without locking up. A teeny bit of finagling the cylinder and hammer and it rotates around and the bolt pops and locks when it should, as it should. Once locked, the cylinder has virtually no play and is nice and tight.
  Any suggestions from the resident revolver experts?

  Thanks in advance,
    CHT

[Coffinmaker]

Two (with out being able to "look at it").  First, insure the bevel at the top of the hand is clearing the window.  If the hand is contacting the  the window, it may well stop everything.  The top of the hand starts everything in motion and requires the bolt to drop before the cylinder starts in motion (you already know that). 

Cylinder carry up is driven by the second step on the hand.  If the second step is not tall enough it will leave the cylinder short of lockup.  In many instances, when cycling the action slowly the cylinder will stop short.  When the action is cycled smartly as in match play, simple inertia will cause the cylinder to carry up into battery.

You should also look at the fit of the bolt to the foreign cylinder... It sounds as if the fit of bolt to cylinder slots is a tad questionable.  My last thought ..... Uberti is in constant flux.  There is the distinct possibility the star of the 15 year old Flat Top is somewhat different than the star of a current production anything. 

Take the Spring, Plunger and tiny miserable little screw out of the gun.  Put them in a nice save parts holder.  When cycling the action, cycle the action with the barrel pointed down at the bench.  Before your cycle it, thump the end of the barrel on your soft leather bench pad.

[Gabriel Law]

This post is useless to your problem.  I bought a pair of consecutive serial numbered Pietta '51` Navies from Marstar, complete with an additional pair of cylinders.  Everything works flawlessly.  I've lost track of which cylinders are original to the revolvers.

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[Coffinmaker]

Gabriel L.,
I hate to tell you this, but your somewhat mistaken.  Or full of Poop if you will.  The differences between Uberti Products and Pietta products are LEGON!!  HUGE.  Entirely DIFFERENT.

Pietta Cap Guns are ALL built on the Pietta version of the 1851 frame.  They are built by CNC.  ALL of the Pietta internal lock works are interchangeable.  Pietta Barrels are interchangeable (very minor fitting).  Pietta Cylinders are "Drop In" once you "fit" the bolt to the Cylinder lock slots.

NONE OF THE ABOVE applies to Uberti.  Wanna try again??

[Gabriel Law]

CM:  I did start out with "This post is useless to your problem".  You cannot compare apples and oranges - that's for sure.  Just as an observation though, I have many Uberti revolvers and love them, but they have all required more 'smithing than my Pietta guns.
The only comparative note I could make:  I have a conversion cylinder for my 1849 Colt pocket pistol (Uberti) in .32 S&W and also one for my Walker/Colt in .45 Colt.  Both of these replacements fit perfectly and function without issue.  Again, I recognize that my post isn't particularly useful.

[riflee]

If the bolt doesn't drop soon enough so the hand tries to turn the cylinder prematurely the problem can't always be remedied by shortening the hand especially if the hand is putting the cylinder in battery simultaneously with the trigger hitting full cock. Shorten the hand and the timing at the end might be set amiss.


The bolt can usually be made to function sooner by getting the bolt leg closer to the hammers cam.  That can be done by filing the bolt on the proper side of the screw hole so then bolt head will go up further in the bolt window which means the bolt leg is closer to the hammer cam and works sooner. A cartridge gun doesn't worry about blow back so the bolt leg can be right on the cam so as the hammer moves so does the bolt move simultaneous with it.  A percussion needs a little play between the hammer cam and the bolt leg to handle blow back. A stiffer main spring or better nipples can come into play.


I'm just saying the fix isn't always shortening the hand since that changes the timing and if the timing was actually right then the timing will be out of wack with a shortened hand. Sort of like shortening the hand could be mistakenly filing the wrong part.


You can work the hammer and watch the bolt and see if it takes excessive movement of the hammer to work the bolt. Having the trigger guard off the gun you can look right down in there and see if the bolt leg is too far from the hammer cam.

Of course if the bolt is filed from the hole toward the bolt head and beyond to the tab on the end of the bolt and the bolt head is then higher then the bolt head may need filed down some. 


Messing with the double pronged hand/pawl  and setting it out of time just causes more tuning to have to be done. Maybe having to make the trigger longer  to have good timing.

It'd better to go right to the proper part that needs filing on. You don't want to file the top prong on a pawl and then maybe then have the lower prong bind on the ratchet tooth.  You know …..if the distance between the two prongs upper compared to the lower is already set up proper you wouldn't want to mess it up.  Just go to the bolt first.


Anywhoooo…..I'm trying to cover both percussion and cartridge guns at the same time but...…..the principal is basically the same for both. You want to work the right part on either. This case at hand I'd venture to say again the bolt is the place to start.   

It's amazing how so few parts can create so many different scenarios of perplexing problems. It's actually surreal at times. Specially when yer getting a little old and it takes a little more effort to thunk it out well.  That's where I've been dwelling a little too often. Off in the 0zone at times.    

You Cowboys should feel sorry for me struggelly to type well and having to remember how to spell stuff and buy me sompthing nice fer Christmas.  No candy canes accepted though.     Just joking! Almost maybe. Just in case. 

I try anywhoooo.
 

[riflee]

Cholla Hill Tirador had the cause of the problem right off the bat when he knew the flat top cylinder was different from the 44 special cylinder. Might just leave the flat top a 44/40 and live with that.

[Cholla Hill Tirador]

 Update-

 Being the weak-willed SA nut I am, I could not resist when I found a new 7 1/2" Uberti Flat Top 44-40 at Dixie Gun Works for the miserly sum of $450. No sooner was it order than was a new .44 Special cylinder. This one fit this revolver easily and perfectly with only a minimal amount of metal needing to be removed from the rear of the cylinder. Once this was done the cylinder fit in perfectly and functioned perfectly with the original hand.

 One day I'll tie back in to the OTHER Flat Top and figure out what's wrong with it. Thanks for all the replies and suggestions.

 CHT