What causes revolver end shake?

[john c]

I'm having a friendly debate with a shooting buddy about what causes revolver end shake. The issue came up discussing the fact that .38 super has a MAP of 36,500 PSI vs. 35,000 for .357 mag. His contention is that since the .38 super has higher pressure, an otherwise identical revolver (L frame Smith) will develop end shake quicker. My contention is that a 158 gr .357 has more energy (539 ft/lbs vs. 492 ft/lbs) than a 130 gr .38 super, and therefore will cause end shake sooner. What do the experts say?

[olstyn]

I'm no expert on revolvers or the cartridges in question, but actual loads don't usually hit max SAAMI spec pressures; I bet if you look around for a fairly short amount of time, you can find .357 loads that have higher pressure than some .38 super loads, and .38 super loads that list higher energy than some .357 loads. Also, you're talking about pretty small differences in the first place - .38 super's max pressure is only 4.3% higher than .357's, and the energy numbers you're quoting are only different by 10% or so. It's probably pretty close to a wash in real-world terms, especially given variations in powder charges in the ammo and variations in materials and construction quality and tolerances in the guns.

[SLG]

Shooting causes it. Specifically, recoil:-)

I don't know for sure, but I think heavier weight bullets cause it way more, and more often, than lighter bullets.

Interesting question and I'm curious to hear more informed information.

[serialsolver]

Tolerance.

Basically when the revolver is fired the cylinder slams back into the frame. This constant hammering back and forth of the cylinder in the frame window when the revolver is fired numerous times causes end shake.

I hope someone smarter and knows more than me checks in and tells us I'm right.


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[DamonL]

Good question. You made me look it up.

http://www.grantcunningham.com/2007/01/the-importance-of-endshake/

[john c]

Good question. You made me look it up.

http://www.grantcunningham.com/2007/01/the-importance-of-endshake/

Yes, but does a higher pressure, but lower recoil round cause more end shake, or does a slightly lower pressure, but higher recoil round do it?

[Buckshot]

Yes, but does a higher pressure, but lower recoil round cause more end shake, or does a slightly lower pressure, but higher recoil round do it?

Kinda a chicken or the egg question, as recoil is a factor of velocity & projectile weight combined, and all things being equal (i.e. powder type), velocity is a factor of pressure.

[rsa-otc]

I can't say whether pressure has anything to do with it, but but lighter bullets loaded hot are notorious for shooting guns loose/premature wear on revolvers. The 125 grain .357 magnums come to mind. Light bullets in 40 S&W also are known for causing excessive wear.

[Jeep]

Microagressions cause end shake. The only solution is to let the revolver be alone in a safe space with coloring books and cookies.

As far as microaggressions, listen to your wrist. Full bore 125 grain screamers will microagress your revolver much more than lightly loaded 148 grain wadcutters. 158 grain rounds loaded to 1400 fps will not only microagress your wrist,; they'll make the revolver unhappy too.

[JHC]

Is end shake detected by side to side play or fore and aft play???? About time I got this straight.

[Willard]

Is end shake detected by side to side play or fore and aft play???? About time I got this straight.

End shake is fore and aft. Depending on the source, the side to side wobble, or rotational play, is referred to as "lock up" or "end play" (and there may be other terms in use as well).

[Wheeler]

It's been my experience that hot loads that exceed the design specifications of the revolver will induce end shake more rapidly. For instance, Skeeter Skelton loads in a 686.