Answer

Is the brass old? Been reloaded quite a few times? Is the load hot? The chamber is right but is the ramp too deep? The headspace can be great and the ramp just too deep.

Reply:

More than likely the brass is old and been reloaded quite a bit. The ramp seems to be okay as does the chamber. The only thing I can come up with is overload

Answer:

Check the primer in the blown case that will tell you if it was a hot load. It will be flat and it will have flowed into or around the firing pin hole some. You know you have seen some I am sure.

Reply:

The Primer was totally blown out of the case head. I cannot even determine if the case was the problem or a double charge. The only information I have is that has happened to this customer twice in two different pistols. Which leads me to believe something with the ammunition?

Answer:

Yeah that is what it sounds like, when the ramp is too deep the case bulges and or ruptures where there is not support but the primer is fine. If the cases were old the same thing would happen or the case head would separate, this sounds like a HOT load. And it happened to the same guy with TWO different guns??? Got to be ammo.

Reply:

Thanks, by the way I took it to the firing range today and it works fine. Am making an appointment with the customer to teach him how to reload.