acceptable case expansion / 38 special

[randy86314]

how much case expansion is acceptable for .38 special cartridges fired in a revolver? some of my chambers permit the cases to expand to .383", which appears excessive because the case bulges primarily on one quadrant of the circumference. do any of you know what the max acceptable diameter is for a fired case? my reamer print from JGS show a max diameter of .380"

thanks for your help

M10, M586, M15, M19

 

[randy86314]

how much case expansion is acceptable for .38 special cartridges fired in a revolver? some of my chambers permit the cases to expand to .383", which appears excessive because the case bulges primarily on one quadrant of the circumference. do any of you know what the max acceptable diameter is for a fired case? my reamer print from JGS show a max diameter of .380"

thanks for your help

M10, M586, M15, M19

 

[Bullseye Smith]

Are you shooting 38 special in a 38 S&W? What model is it, and what does the barrel say on it?

 

[Alk8944]

randy,

.38/.357 chambern dimension is a minimum of .3801 + .004. so anything less than .3841 is within tolerance. The reason you are seeing all the expansion on one side is the case lays on the bottom of the chamber due to gravity, and when fired all expansion is toward the top.

If you pay close attention when extracting the fired cases you will see that, with a few exceptions, all will be expanded most toward the outside of the cylinder, that is up when that chamber is in firing position.

 

[Pitdog02]

I shoot the same ammo (158gr 357) in my 340 pd titanium cyl and my pre 27. The 27 kicks the empty cases right out the 340 empties have to be pulled by hand. Why so much more exspansion in the 340? If thats what it is.