What is the definitive test for sprung crane on a Colt?

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Russ57

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I have an Colt OMM that was gift from my brother. It has appears to have seen a lot of use.

For reasons I'm not quite sure of yet, the gun isn't as accurate as I would expect. Certainly not as accurate as my brother's OMM.

I'm beginning to suspect the crane is sprung. Pushing sideways on the front of cylinder or ejector rod shows a gap opening up right under the barrel. Would a range rod prove a gun has a sprung crane?

Additional info that might be relevant; primer hits are a little off center and I get leading in the cylinder throats. The gun has excessive end shake (0.008") but it does look like the vintage that can be shimmed (serial number 900XXX). It won't carry/lock up until the hammer starts to fall, but then it locks up tight

Mostly I'm trying to get a handle on where my focus should be and getting a idea on what it might cost to make it right. A sprung crane isn't too bad. Ratchet wheels, latch pins, building up frame holes, stretching hands, etc.....well might be better served to look for one with less wear.

Thanks in advance and I understand nobody can say much without seeing it.
 
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To answer the question, about the only true method of positively identifying a sprung crane is to use a crane thimble.
This is a precision gauge that fits on the end of a disassembled crane that will enter the frame latch hole if the gun is not sprung.
No one sells this, you have to make one.
A range rod is useless for this purpose.
To see it, get a copy of the Kuhnhausen Shop Manual on the Colt DA revolvers, volume One.
That shows the gauge and how to use it.

https://www.midwayusa.com/product/1014291858?pid=369326

Another cause of cylinder-crane looseness in the frame is just a worn gun.
Wear to the frame latch hole, the latch pin and it's fit to the pin's hole in the frame, or a worn ejector can allow a loose cylinder.
Repair totally depends on what's wrong, and often that calls for a Colt qualified expert.
 
...the only true method of positively identifying a sprung crane is to use a crane thimble.
This is a precision gauge that fits on the end of a disassembled crane that will enter the frame latch hole if the gun is not sprung.
No one sells this, you have to make one.

Does Brownells no longer sell them? They did sell Colt specific crane thimbles at one time as well as S&W yoke alignment rods.
 
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