Ruger SP101 Endshake

[ITman 2]

I have a question for all you revolver experts. I have two Rugers, a 5" GP100 and a 3" SP101. Both were purchased new and have only about 500 rounds through them, 50% 357 magnums and 50% 38 specials. Both function fine so far. As I learn more about revolvers I was reading about end shake so I got out my feeler gauges to measure the end shake on my Rugers. The GP100 felt real tight with little forward/backward movement of the cylinder. I measured .006" with the cylinder fully back and .003" with the cylinder fully forward so as I understand it that gives it an end shake of .003".

The SP101's cylinder always felt a bit loose compared to the GP100. Measuring the forward/backward movement of the SP101's cylinder I got .003" forward, .008" backward so the end shake is .005".

Would anyone know if I should be concerned about the end shake on the SP101? Is installing a end shake bearing something easy to do to correct or would a gunsmith be needed to install it.

 

Thanks for any advice!

[Pizza Bob 1,488]

I would contact Ruger and ask them what their acceptable end-shake dimension is - without telling them up front what you have. The GP100 is fine. I would say the SP101 is borderline (I have seen gunsmiths state that .002" - .005" is acceptable on the SP101) - may be perfectly fine, given the tank-like dimensions of Ruger frames you may never experience frame "stretch". Ruger may consider your .005" perfectly acceptable - so it would be pointless to send an "in-spec" gun back. If you are having a problem with the gun, that could concievably be linked to excessive end shake, then by all means, make sure they know that. First step, though, is to get what is acceptable from the manufacturer.

 

Adios,

 

PIzza Bob

[GRIZ 3,369]

I agree with Bob. The is no way the number of rounds you've fired caused end shake. If your SP101 has end shake is if it left the factory that way. Call Ruger like Bob says.

[NJCK 5]

Your SP101 is within tolerance, but it is currently at the maximum per Ruger's spec. If you've peened the ratchet column and/or recoil shield, the frame will need replacement. Ruger may not act on it yet given it's technically within their spec, BUT if you push the cylinder all the way forward and you drag they'll take action on it.

[ITman 2]

I would contact Ruger and ask them what their acceptable end-shake dimension is - without telling them up front what you have. The GP100 is fine. I would say the SP101 is borderline (I have seen gunsmiths state that .002" - .005" is acceptable on the SP101) - may be perfectly fine, given the tank-like dimensions of Ruger frames you may never experience frame "stretch". Ruger may consider your .005" perfectly acceptable - so it would be pointless to send an "in-spec" gun back. If you are having a problem with the gun, that could concievably be linked to excessive end shake, then by all means, make sure they know that. First step, though, is to get what is acceptable from the manufacturer.

 

Adios,

 

PIzza Bob

Thanks Bob, I'll give Ruger a call and see what they say.

[ITman 2]

Your SP101 is within tolerance, but it is currently at the maximum per Ruger's spec. If you've peened the ratchet column and/or recoil shield, the frame will need replacement. Ruger may not act on it yet given it's technically within their spec, BUT if you push the cylinder all the way forward and you drag they'll take action on it.

At what point could it become unsafe to fire if at all? I mean if the end shake worsens and goes to .006", .007", etc?

[NJCK 5]

At what point could it become unsafe to fire if at all? I mean if the end shake worsens and goes to .006", .007", etc?

 

There are two things excessive end shake results in: 1) misfires due to light primer strikes because your cyclinder moves too far forward, and 2) your cylinder can come open unexpectedly. At .005" you're at the maximum, and that cylinder becomes a battering ram with each load through. Simple physics works here: the greater the shake, the worse the peening. If this is new, it's easily corrected with bearings (super thin washers). If it's been awhile, might be too far gone. On a Ruger, I don't recommend the quick fix that basically stretches the crane tube. If you're the original owner, Ruger should take care of you. If not, a competent revolver smith should inspect and see if the bearings will work.