Cylinder movement

[Citroen]

Not sure if this should go here or in Gunsmithing - please move if in wrong forum.

My 25-2 Smith is shot a lot. When I cleaned it today, I checked the cylinder movement - back and forth - and found it to be .005. Method of checking was to push the cylinder rearward and pass a feeler gauge through the gap at the barrel with the cylinder pushed to the rear - gap was .012; then to push forward and again check the gap - .007.

Conclusion was the cylinder movement was .005. Should I install a .002 shim to reduce this movement or is .005 within specs?

Thanks for any help on this.
John
Charlotte, NC

 

[dfariswheel]

On the S&W 0.005" is in spec but getting close.

On the S&W, it's OK until it gets to 0.006".

Colt's are a lot closer spec. For the Colt, 0.000" to 0.003" is it.

 

[Citroen]

Thanks.
JOhn

 

[Old Fuff]

Yes and no....

I would consider .005" endshake to be excessive, and likely to get worse. But there is a lot more to correcting the situation then simply dropping a shim (called a "bearing") inside the cylinder. Done right the yoke barrel should be reamed, and then another cutter used to square the end. At this point you mght need two .002" (or one .004") bearings, and would end up with about .002" remaining endshake, which is O.K. The tools and bearings together will cost near $100.00.

You can ignore the reaming and squaring of the yoke barrel, but if you do the endshake will likely come back. Whatever you decide. www.brownells.com have both the bearings and tools. Keep in mind that after you correct the endshake the cylinder/barrel gap will be increased to .010" give or take. If you shoot lead bullets that would be considered acceptable, but at the outside limit.

 

[Citroen]

Thanks, Fuff. I understand that installing the bearing is not a real fix but it certainly is easier to try. I have the bearings in both .002 and .004 and thought that the .005 was excessive.

I do shoot lead as well as some plated bullets and use the gun in USPSA. I think that the excessive movement forward might contribute to an occasional failure to fire with anything other than Federal primers so was hoping that reducing the movement would allow me to use other primers as Federal are hard to find.

Incidently, that gun came from a dealer in Prescott, AZ; I bought it when I was at Gunsite in 1985 so it has seen a lot of use. Prior to shipping the gun to me I had the gunsmith there do a lot of work on the action and bevel the cylinder for faster reloading.

Thanks again,
JOhn
Charlotte, NC

 

[Old Fuff]

Load your chambers with the ammunition you usually shoot, and then use your feeler guage to measure the clearence between the back of the cartridge to the breechface. Check each chamber while holding the cylinder forward as far as it will go, and then with it back as far as it will go. Don't use any clips when you do this.

The cartridges are supposed to headspace at the front of the chamber, but I have known of cases where the chamber was too deep. In that case the cartridge is positioned (more or less) by the half or full-moon clips you use.

Unlike the Government Model pistol, the firing pin in the revolver can't reach out to hit the primer. Your ignition problems could be caused by endshake, which opens up the headspace, too deep chambers, a modified mainspring or short mainspring tension screw, or a combination of any of the above.

This is one reason I prefer rimmed cartridges in revolvers...