GP100 endshake repair and cylinder play questions

[FullEffect1911]

I posted this in the revolver section but, in retrospect I probably should have posted it here (I apologize to the mods in advance for my error).

Anyway here goes.

I have a few questions about my gp100. First the gun shoot great and isn’t spiting out of the barrel cylinder gap as far as I know.

But there is a slight end shake condition of .003” to .006” from measuring on the B/C gap with feeler gages. From reading the revolver checkout thread and learning more about revolvers I believe that even though some people say Rugers can handle some end shake, I just can’t see how this is a good condition to have. So I would like to purchase some end shake bearings from Midwayusa (they have them for the GP) and fix the problem myself. A .002” end shake bearing should give me a B/C gap of about .005”-.006”.

What is the procedure for installing these bearings once the cylinder is off the firearm? Is there other tools I will need in order to do the job right?

Also as a point of confusion on my part I have a question about revolver checkout. With the gun is EMPTY, full lockup, looking down the barrel and shining a light to check for proper timing. Do you allow the cylinder to remain at rest or do you try and use the rotational play to get it out of alignment? I would assume that you would check this while the cylinder is at rest as it would be at the point of firing, but I would like to just make sure.

I look forward to any insight on these topics.
FE1911

 

[JimmyN]

Are you checking end shake with the cylinder in full lock up? I know you stated you checked alignment at lock up, endshake measurements must also be at full lockup. (hammer down, trigger back)

Alignment check at rest is good, that's where the cylinder will stop in normal use.

.003 end shake is within Ruger specs, they allow up to .007, though many feel that is excessive and I've never actually seen one with that much play. Your B/C gap at .006 is in range, with a maximum of .008 allowed.

Actually I would just continue to use it, everything is within spec, and check it periodically to see if the play is increasing. If so then use an endshake bushing to correct it. If it wasn't in full lockup when you checked it you may find it has much less end shake than you thought.

 

[Old Fuff]

Checking end shake has nothing too do with where the hammer and trigger are in a Ruger revolver. You are checking back & forth cylinder movement, not rotational lock-up. You first check the gap while holding the cylinder all of the way back as far as it will go, and then do the same while holding it as far forward as it will go. The difference in measurements equals the end shake.

Holding the trigger back all of the way will affect older pre-1970's Colt's but not Smith & Wesson or Ruger revolver's rotational lock-up; because the hand rotates the cylinder until the bolt is wedged against one side of the cylinder notch on the Colt's but not the others.

 

[Jim K]

Colt always bragged that their revolvers "locked up tight" when cocked, and quite a few "experts" will insist that there must never be ANY rotational cylinder movement when a revolver is cocked. But what Colt didn't say is that their system of forcing the cylinder against the cylinder stop (bolt) could force the cylinder OUT of alignment if there was wear in the bolt or cylinder notches.

S&W's are always a bit loose in that area and S&W says not to worry as the bullet itself will line up the cylinder and barrel. Sounds a bit "iffy", but S&W's shoot OK.

Jim

 

[FullEffect1911]

S&W's are always a bit loose in that area and S&W says not to worry as the bullet itself will line up the cylinder and barrel. Sounds a bit "iffy", but S&W's shoot OK.

I posted about this where I originally posted this thread which is in the revolver forum. From looking further into these things the way I understand it is, that without the rotational play, if the cylinder hole to bore line up wasn't perfect, then it would cause shaving and accuracy would degrade. So that play is actually designed into the system for proper function. I'm not as concerned about rotational play as I was just two days ago.

 

[TOGGLELOCK]

Ruger increased the barrel/cylinder gap in the Security Six series. This because of powder change from a prominent law enforcement agency. The GP100 runs a bit large and I seem to remember correctly that this is normal to have a larger gap in the Rugers. Remember, hold the cylinder forward all the way and measure. That's your BC Gap. Then hold back and measure is the End Shake. Don't worry, and stop trying to over analyse the situation. FYI, I attended the Armorers School and was impressed by the class. When in doubt, send the gun to Ruger for a checkup. Too many so called "Gunsmiths" don't know what the factory knows about their own guns....... TOGGLELOCK