Uberti Colt 1863 timing?

[Walt-MT]

Hello the board!
I'm in a jam with an 1860 Army after a broken cylinder bolt replacement.( Uberti made, date mfr. XXV = 1979 ?)

Prior to the bolt spring breaking, this arm fired incredibly smoothly and had been tuned by someone; it worked well.

The new bolt is fitted and moves freely on the screw and actuates when the cam on the hammer slides past it. I don't seem to be able to time it closer then an eighth of a cylinder turn before the lockup. This is galling and dragging the cylinder terribly.

This is followed by the bolt apparently not releasing this cylinder before the hand (pawl ?) puts tension on the cylinder so that when the bolt finally clears the slot the cylinder will spring past the next chamber position. I suspect bolt fitting here is incomplete.

I have run out of knowledge; how does one retard the lifting of the bolt to a point closer to or within the cylinder notch? I am concerned about over-filing the left side of the bolt (when looking from the top) but can't see another way or another cause of the cylinder being preloaded by the hand and then releasing too far.

As a last question, 1970s production Uberti... 12 - 28 threads are too loose and modern Italian metric are too big.
The major diameter on the existing cone threads is approximately 0.231 as compared to new Treso nipples at 0.215 for 12-28 ?!?

Any help would be greatly appreciated as I am supposed to demonstrate with this gun this weekend. (not looking likely)

Thank you,
W. Abbot

 

[Jim K]

First, the part of the bolt you are concerned with is the left arm, looking at it from the rear. The other arm only provides tension. The bolt is operated by the round cam on the hammer. It raises the rear end of the bolt, pulling the front out of engagement in the cylinder notch. The bolt drops (actually it comes up, but the term is "drop") when the cam moves past the tip of that arm. If the side of the bolt is slipping off the cam, the bolt is not shaped right or there is not enough spring tension. (The bolt is its own spring for that engagement with the cam.)

From your description, I am not quite sure what the problem is. Once the bolt is drawn out of the cylinder notch, the cylinder should turn almost to the next chamber before the bolt drops again. Ideally, it should drop into the leade (the triangular cut leading into the notch), but sometimes they do drop a little sooner. The bolt spring should be tuned so that the bolt doesn't gouge the cylinder even if it does mar the bluing. Also the top of the bolt should be stoned to remove sharp edges that can scratch the cylinder.

Jim

 

[madcratebuilder]

Sounds like you do not have enough tension on the bolt leg and it's needs to be tighter against the cam. Try bending the leg just a bit at a time and test fit until the bolt drops and raises at the correct time.

Your nipple size for the Uberti 1860 Colt Army is 5.5mmX.9mm.

 

[Old Fuff]

The problem may not be the bolt.

Before you do anything be sure the stud or "cam" on the hammer isn't worn. In the original revolvers it was a seperate part that could be replaced, and it was also case hardened. In the reproductions it part of the investment cast hammer, and usually not hardened. Since the bolt is actually harder then the cam, the cam can be easily and quickly worn. When this happens the tail end of the bolt slips off too quickly and the bolt is released too soon.

Also be sure that the replacement bolt was made by the same company that made the gun. All bolts are not created equal.

As they come from the manufacturer, bolts are not "drop in" parts. Extra material is left at certain fit points so that they can be fitted by a gunsmith. If you understand how to fit a bolt, carry on. If not you'd be better off to find a gunsmith who is experienced in doing this kind of work.

One last hint. There is far more information available on how to fit a bolt in a Colt Single Action Army then the cap & ball revolvers, but fortunately they both work the same. Advise for one is good for the other.