View Full Version : Cylinder End Play

February 7, 2002, 09:41 AM
When measuring the cylinder "end-play" on the GP-100, Do you do that with the revolver in lockup or with the cylinder open.
Also what is the ususal cause for excessive end play. ;)



February 7, 2002, 10:07 PM
Properly called cylinder end-shake. It can only be measured with the cylinder in the closed position. End shake is how much fore-and-aft movement of the cylinder there is.
The usual causes are wear and tear, and over pressure loads.
Wear and tear is accelerated by a dirty or unlubed gun.
Over pressure loads stretch the frame or compress the cylinder's recoil collar.
Once the cylinder develops end shake, it gets worse due to the cylinder slamming forward against the cylinder recoil collar, bouncing off the recoil collar, and slamming backward against the breech face.

February 7, 2002, 10:30 PM

So the cylinder end-shake, that is noticable with the cylinder open is not a worry in moderation. Thats Good as I have less then .001 with the cylinder closed. With a cylinder gap of .005


James K
February 7, 2002, 10:41 PM
That sounds fine to me. In fact the gap could be a bit more; too little gap can cause binding when the cylinder heats up, but that is not likely to be a problem in normal use.


February 8, 2002, 12:17 PM
Can anything be done to fix this?

February 8, 2002, 03:05 PM
I called Ruger and asked them what the spec's were for End Shake on a GP-100. She had to call me back so she could find someone with that Infomation. When she called me back she said it was .066-.068. Go figure.


February 8, 2002, 03:23 PM
Tony.....and yet another good reason to second source critical stuff.


February 8, 2002, 05:30 PM
Y'know, I COULD be wrong here, BUT...those numbers the "Ruger Girl" gave you sound suspiciously like the specs for HEADSPACE, NOT cylinder end-shake...I don't believe I've EVER seen a decent-quality revo with that much "endshake"...at least, not one that wasn't inoperative or BROKEN-!!!...now, if it was an "FIE" or "RG", well...that's a different story!!!....mikey357

February 8, 2002, 07:27 PM
Yes, end shake is correctable. How, depends on the brand of gun
and what method you want to use. For example, S&W guns can be repaired by either stretching the yoke barrel, (the tube the cylinder revolves on) or by putting in hardened stainless washers.
Colt revolvers are repaired by stretching the cylinder collar, or replacing the ejector ratchet.

James K
February 8, 2002, 08:37 PM
Amen, Mikey. I am not one for excessive worry about endshake, but I sure don't want to shoot a revolver with .066" of it! I agree that whoever gave her the info was thinking of headspace.

If there is zero end movement, and depending on the gun design, cylinder heating can cause binding, just as too little barrel-cylinder gap can. Tolerances have reasons, believe it or not.


February 8, 2002, 08:52 PM
Yeah, I thought so...FWIW, I read a piece authored by "Scary" Jerry Miculek a number of years ago, in which he said he tried for .005-.006 in. barrel/cylinder gap AND .001 in. ENDSHAKE in his COMPETITION revos...he seemed to be of the opinion that it was possible to make a revo TOO "tight"...sounds reasonable, ESPECIALLY considering the number of rounds he's fired, both overall, and at one time, as in extended practice sessions or demo's....mikey357

February 8, 2002, 09:19 PM
You can certainly make a revolver too tight! I had that experience on one of the smallest revolvers around, the NAA mini-revolver. I got one that seemed to have an unusually large gap, and I sent it back for them to correct it. I got it back, and the gap was then about .003, but it seemed to function fine. I took it out, and after about 3 shots, it would bind, just that small amount of temperature rise would jam it. I sent it back and it came back with .007, and that worked fine.

February 8, 2002, 10:22 PM
Jim Keenan & mikey357

I did check the headspace with some feeler gauges put togeather and came up with .063 there abouts. So looks like you were right. Guess I'd better call back on monday, and try again. I would at least like to now that the maker of the revolver knows the spec's.
The gun works and looks like new. It is the most accurate of all my 38/357's.
I just drop in a wolffs reduced trigger spring and reduced main spring, Polished the hammer, sear and related parts with my drummel, WOW:) what a differance in the trigger.:D