I often read that there should be 0 end shake during lock up. I read that S&W's limit is .0015", and .005" is over three times that.
Howdy Again
I have no idea where the OP came up with the figure of .0015 being the 'limit' or that there should be 0 endshake.
I went to my favorite source on all things S&W, Jerry Kuhnhausen's The S&W Revolver, a Shop Manual.
Kuhnhausen only states, as far as S&W revolvers are concerned, that .001 of endshake is ideal. He has no figure for what is the max.
Then I turned to Kuhnhuasen's book on the Single Action Army. In this book, he states ''Whether bushing and base pin diameters are within individual specifications is less important than aggregate cylinder bore/base pin bushing/base pin/frame base pin hole clearance. Original ordnance specifications called for zero perceptible vertical cylinder play and endplay when the cylinder was installed in the frame."
Translation: once everything has been adjusted, there should be zero endshake. Notice he does not specify a maximum allowable amount of endshake in this book either.
Finally, I referred to Kuhnhuasen's book about Ruger Single Action revolvers. (Sorry, I don't have his book on double action revolvers. I only have one, so I never bought that book)
In this one he states that as close to zero endshake is desirable. He also mentions "Cylinder endplay causes variable headspace and variable barrel/cylinder clearance and, when excessive, can also cause the cylinder to thrust rearward and slap seat against the frame ratchet bearing surface on firing. Past a point excessive cylinder endplay can also cause variable ignition and misfires, particularly in revolvers with minimum, or less, firing pin protrusion and /or reduced tension mainsprings".
This statement about the possible injurious affects of endshake would be true with any revolver.
Notice that again in this book he states zero endshake is desirable, and he mentions a few bad things that can happen with excess endshake, but nowhere does he give a figure for what he considers to be maximum allowable endshake.
It should be stated at this point that Kuhnhausen's books are manuals for gunsmiths. Rather than stating maximum allowable amounts of endshake, he covers in detail various ways to fit a number of components, to get endshake down near zero.
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Next, just for the fun of it, I pulled out a few revolvers, just a small sample, and did some measuring.
Let's start with Smiths.
Model 17-3, 22RF, made in 1975, .003 of endshake.
Model 14-3, 38 SP, made in 1974, .002 of endshake.
Triplelock, 44 SP, made in 1915, .003 of endshake.
K-22, 22RF, made in 1935, .005 of endshake.
Model 617, 22 RF, made in 2003, .001 of endshake.
Model 686, 357 Mag, made in 2015, .002 of endshake.
Let's look at a couple of Colts
SAA, 2nd Gen, 45 Colt, made in 1968, .003 of endshake.
SAA, 1st Gen, 38-40, made in 1909, .006 of endshake.
A few Rugers
Blackhawk, 45 Colt, made in 1975, .004 of endshake.
Vaquero, 45 Colt, made in 1993, .004 of endsake.
GP 100, 357 Mag, made in 1997, .002 of endshake.
I noted the dates to show that over time, endshake can increase. However I have no data to show that the frames of any of these guns have actually stretched over time, that they did not leave their respective factories in the condition they are in today. It is interesting to note that the old K-22 has .005 of endshake. I doubt if recoil from 22 rimfire ammo would have stretched the frame.
Also interesting to note is the 2nd Gen SAA with .003 of endshake. When I bought this gun about ten years ago it was my first Colt. I noticed it had some endshake. A gunsmith told me endshake is bad and will increase over time. He was probably referring to what Kuhnhuasen calls 'slap seating'. I can categorically state that after ten years of firing nothing but heavy recoiling 45 Colt Black Powder loads in this Colt, the endshake has not increased. .003 seems pretty acceptable to me. The .006 of endshake in the 1st Gen Colt is pretty excessive, but hey, the gun is almost 110 years old.
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Is .005 of endshake unacceptable in a brand new Ruger LCR? I really have no idea. Based on my very limited sample, it does seem a bit excessive. I could measure a whole lot more revolvers, but I really don't feel like it right now.
It should also be mentioned that part of Bill Ruger's genius was designing firearms that could be assembled by relatively unskilled assemblers. Not true with the glory days of Colt and S&W. Assemblers in those factories were skilled craftsmen who hand fitted parts to exacting fits. That is exactly what Bill Ruger was trying to avoid, he was trying to drive the cost out of assembling his firearms. So he designed them so they could pretty much be assembled by unskilled assemblers dropping parts in straight out of the parts bins with no fitting. The only way to do that was to increase the tolerances of the parts, so individual fitting was not needed. It follows that with looser tolerances, a certain amount of slop would creep in. My point is, and I will freely admit I have only handled a Ruger LCR once, I would not be surprised if a bit of slop has crept into the LCR assembly line. On the other hand, I was quite surprised to find the GP 100 I own only has .002 of endshake.
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