Need opinions on cylinder to barrel tolerances on a Uberti cattleman

[Marshal Deadwood]

I have a Uberti cattleman ,,,and the cylinder to barrel space concerns me since its a new gun under warrenty.

The manual says between .004 and .008,,,and it gauges at .010 ?

Will that create enough of a 'cutting tourch flash' to be a consideration of calling the tech dept?

What'cha think folks ?

Marshal Deadwood

[Driftwood Johnson]

Howdy

Kuhnhaused says a barrel/cylinder gap of .006-.008 is optimal. However, properly measuring barrel/cylinder gap assumes zero endshalke. Endshake is the amount of free motion the cylinder has forward and backwards along the cylinder base pin. Ideally, endshake should be zero, but zero endshake is rare. .001-.002 is common. One cannot accurately determine barrel/cylinder gap without taking endshake into account. Just slipping the largest shim possible into the gap does not account for endshake.

To determine if you have any endshake, or how much; measure the barrel/cylinder gap with the cylinder pushed completely back and with the cylinder pushed completely forward, while the hammer is in the half cock position. The difference between the two measurements will be your endshake.

If you have determined you have zero endshake, then you really do have a b/c gap of .010. However, if any endshake is present, pushing the cylinder all the way FORWARD, while shimming the gap, will determine your true b/c gap.

Bottom line, while .010 is a bit excessive for a barrel/cylinder gap, I doubt it will have much significant effect on increased flame cutting of the backstrap. You may notice a slight decrease in velocity, but with just .002 over the normal max, even that will be dificult to determine.

[Marshal Deadwood]

Driftwood,,,,I tried your advice and I can find no measurealbe or even fellable endshake. This cylinder locks up with -0 moventment forward or backwards...so the shims tell me and I can feel no movement at all.

The cylinder also locks up with no movement or,,side to side/rotation direction shake. It seems percise in all those reguards,,one of the most solid locks up iv seen in a cylinder on any revolver,,,back and forth or side to side.

Thanks for you advice, it appears that a constant .010 is what the cyl/bore gap is.

I was just concerned about  the .002 over tolerance.

Perhaps all is ok then. I DO tend to be some what a worry wart over such things....

thanks again

Marshal Deadwood

[Driftwood Johnson]

........ I DO tend to be some what a worry wart over such things....

I've noticed. Just for the fun of it, try the sliding front to back thing with the cylinder in the onlocked condition, with the hammer at half cock. When the cylinder is locked at battery, lockup will mask any slop.

[Marshal Deadwood]

Driftwood,,,Iv tried it at every concivealbe location possible,,half cock, battery, between roataions,,,nothing,,,solid as a rock,,,no,,absolutly no forward/backwards movement at all.

Marshal Deadwood   

[Flint]

So if you have zero endshake, you have a jewel there, so don't worry about the .010 cylinder gap, especially if you want to try black powder, that will give you some room for fouling. 

The work necessary to pick up another .002 to .004 gap reduction would not pay off in noticably  increased performance on a CAS range.  The barrel would have to be removed, put in a lathe and trimmed to rotate another turn deeper into the frame, then recut for a new cylinder gap, then the ejector rod housing shortened to match the new screw hole location.  Very unnecessary money and work for a minor gas leak.

Another method that requires a welder who knows his stuff, is to remove the barrel and add steel to the barrel extension then re-square, re-throat and reshape the barrel extension for a reduced cylinder gap.  I did it on an ASM Dragoon with a mile of gap, but I don't know that I would do it to a cartridge gun.