Is End Shake Desirable?

[FrankB]

I’m having a barrel swap done, and my fine gunsmith said that he shoots for .003” of end shake. Said it helps with thermal expansion, but I’m not a competitive shooter. Any thoughts?

[Norville]

I know there is a spec on it, and it isn’t “zero “, so some is necessary for the thermal expansion and dirt build up that is inevitable.

Too much will lead possibly to light strikes, but 0.003 sounds reasonable.

[Stephanie B]

I’m having a barrel swap done, and my fine gunsmith said that he shoots for .003” of end shake. Said it helps with thermal expansion, but I’m not a competitive shooter. Any thoughts?

That's excessive, according to the Kuhnhausen S&W shop manual (page 34, 5th Ed.). He says that anything over .002" should be repaired.

[SiriusBlunder]

It depends on the manufacturer & model.

For example, Ruger's DA spec is looser than the S&W one posted.

[Rock185]

Just as Kuhnhausen suggests, I shoot for ~001". I would consider .003" excessive. Easier for the gunsmith, but would be unacceptable to me ....ymmv

[FrankB]

That's excessive, according to the Kuhnhausen S&W shop manual (page 34, 5th Ed.). He says that anything over .002" should be repaired.
That was my understanding, Stephanie. This is what he told me: “I aim for .006 to .007 max gap with about .003 of end shake which equates to a .003 min gap.”

Maybe he hit the wrong number while typing his email.

[Outpost75]

Setting barrel-cylinder gap to not less than 0.003" pass and 0.004" hold provides sufficient clearance for free cylinder rotation with thermal expansion and normal accumulation of powder fouling. Mean Assembly Tolerance in a new revolver before proofing is 0.005 pass/0.006 hold. In .357 Magnum it is normal for gap to open up to 0.001" in proofing.

Head clearance from the firing pin bushing in the frame with rear gage in place should be in the range of 0.001-0.002" and the headspace dimension from the rear face of the cylinder in .38/.357 0.059-0.062 before proofing and 0.065 max in customer service.

Intentionally fitting a gun with more than 0.002" end shake, rather than properly fitting the cylinder yoke, bushing and extractor to have correct barrel-cylinder gap and adequate head clearance for free cylinder rotation dimensions is "jackleg". End shake which can be "felt" (about 0.003") absolutely should be corrected, otherwise forceful longitudinal slamming of the cylinder during recoil will eventually stretch the topstrap and peen the frame to loosen the gun further if shooting anything heavier than .22 LR or .38 wadcutter...

[jtcarm]

That was my understanding, Stephanie. This is what he told me: “I aim for .006 to .007 max gap with about .003 of end shake which equates to a .003 min gap.”

Maybe he hit the wrong number while typing his email.

https://uploads.tapatalk-cdn.com/20210518/6fa116b1fde0c7d2779c28dd31f01bf8.jpg

[LtDave]

In response to the OP’s original question,

NO.

[Trooper224]

A few years ago I acquired a S&W M29 that had excessive endshake, really excessive. I gave it a tune up and also replaced the hand a couple of months later when the original broke. The cylinder now locks up tight as a bank vault, with zero endshake or side play. Roughly 2k rounds later it has yet to seize up due to any heat expansion. my vote is, "No". In years past, I'd been told by a couple of old time revolver smiths that necessary endshake was a myth or a lazy mans excuse for fitting up a revolver. I tend to agree.

[FrankB]

It didn’t have end shake when I gave it to him, so I’m assuming he’d have to cut the yoke barrel. My son bought a couple of 100 round packs of really hot .357 magnum rounds, and gave me one. I blasted through the entire bag as quickly as I could reload, and didn’t experience any thermal expansion. Just lots of laughs and hoots from the usual suspects at the range. I called the go between today, and told him NO END SHAKE. If it does have end shake, I have a yoke stretching tool. There aren’t many gunsmiths around here, at least none that I know of.

[FrankB]

Got the gun back today, and it’s perfecto! I need another set of boot grips, but they’re on the way. Shot Federal 158gr JSP .357 magnum.
Barrel lengths on revolvers are 3”, 2.5”, and the lonely 4” that was swapped out. There might be some undetectable end shake (I can either feel nor measure any), and B/C gap is a tad under .006”. PERFECT! It’s amazing that .5” can look so much longer, and 1” can appear so much shorter.
71883

[That Guy]

If it does have end shake, I have a yoke stretching tool.

Does it take a lot of skill to use one of those correctly? I just looked it up and Brownells would be willing to sell me one, and the price isn't even that bad.

[FrankB]

Does it take a lot of skill to use one of those correctly? I just looked it up and Brownells would be willing to sell me one, and the price isn't even that bad.
To be honest, I simply took a pipe cutter, and ground the cutting wheel down to 1/16”. I use the closest fitting drill bit as a mandrel, and go slow. It works wonders on older gun.
That Guy. Here’s the tutorial I originally used:

https://youtu.be/EdbzzXXNYxI

[OlongJohnson]

There is also the shim option.

https://triggershims.com/

A lot harder to screw up.

[That Guy]

Yeah, improvising a tool to do something I've never done before and can't reverse doesn't seem like a good idea. If I'll stretch the crane, I'd better do it with an appropriate tool.

Brownells does also sell Power Custom's cylinder bearings. The thought occurred to me too that the likelihood of messing up would probably be reduced by using those. Unless there's more to it than disassemble gun, add spacer, reassemble gun? We're talking about a Ruger revolver in my case.

[FrankB]

Shimming requires more disassembly. Stretching is simply a matter of separating the cylinder and yoke. It is important to have the proper mandrel size, or in my case, plenty of drill bits to choose from. As far as the tool is concerned, Brownell’s tool is just a pipe cutter with the cutting wheel ground wider. Ordinary pipe cutters are cheap. The cutting wheel pops out with one C clip, and can quickly be ground down by chucking it in a drill, and running it against concrete. I have used shims in the past, and they work fine.

[RevolverJIM]

To install the end shake shims, it's necessary to completely disassemble the cylinder.

Be careful when removing the ejector rod, on newer S&Ws it's a "righty/loosy, lefty/tighty" thread.

[Wingate's Hairbrush]

On a S&W, endshake is desirable and necessary for proper function, and deliberately built in to the design; approximately .001" is ideal.

Stephanie's Kuhnhausen quote surprised me; I distinctly recall the shop manual stipulating that endshake didn't need repairing until around .005" to .006", but don't have the book in front of me. Kuhnhausen suggests combining the yoke stretch and shim methods for best results: stretch to .003" endshake remaining, then use a .002" shim.

Stretching is the factory method. To each their own, but proper tools and training I'd argue are the way to go with many revolver fixes, and this is one of them. For instance, to do it correctly, you can't just stretch the yoke and call it good; you're supposed to slightly overstretch it, then use a yoke face cutter to remove a little material and have a properly squared yoke face.

[RevolverJIM]

And it's surprising how "unfinished/unsquare" some yoke faces are.

[OlongJohnson]

And it's surprising how "unfinished/unsquare" some yoke faces are.

Not if you've had more than one S&W apart and looked at everything closely.

[Trooper224]

Sometimes, things aren't necessarily best simply because they're the old way. Khunhausen wasn't the be all end all of gunsmithing knowledge, even though his books are still an excellent resource. Stretching a yoke may be the old way, but that doesn't make it the best. The issue with stretching is, the yoke is fairly thin to begin with and it can only be stretched so many times before the yoke is unusable. If your revolver is anything other than a collectable, you'll be tightening it up more than once. Try to locate a yoke for your vintage S&W of choice and see how easy it is (and assume it isn't well used, they're all used at this point). Shimming doesn't alter the condition of the parts involved and can be dome repeatedly to keep a revolver is service. (Kuhnhausen recommended shimming BTW)

Endshake is a tolerance, not an ideal.

[RevolverJIM]

Not if you've had more than one S&W apart and looked at everything closely.

I've seen it many times..........
What's surprising is that this stuff gets out the door:(

[Borderland]

There has to be a yoke in here someplace.

[FrankB]

Well, the one time I stretched a yoke, it took remarkably little pressure, and just a few turns to get .002” eliminated. I can’t find the trimmer that Power Custom used to sell.

[RevolverJIM]

I don't think Power makes them now.

I haven't been able to locate one any where:(

[OlongJohnson]

Just need the right size pilot.

https://pacifictoolandgauge.com/barrel-crown-tools/10657-interchangeable-pilot-muzzlecylinder-45-chamferingcrowning-cutter.html

I'd call to confirm minimum ID it cuts, but it should work nicely.

[FrankB]

I don't think Power makes them now.

I haven't been able to locate one any where:(

I wonder if Smith&Wesson has any... 😳🤣

[FrankB]

Double Post

[RevolverJIM]

I wonder if Smith&Wesson has any... 😳🤣

If they do, they've probably never been used:)