Historian
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Signs of Over-Pressure in .40 S&W?
I just finishred cleaning and sorting some .40 S&W brass that I fired at the range today. As I was sorting it, I noticed that there was an unusual raised area around the strike dimple. Under a magnifying glass, it became clear that this area was formed by the primer pressing on the firing pin hole. The outline of the firing pin hole from my M&P was clearly imprinted on the spent primer. I immediately began to wonder if these loads were too hot. I used CCI 400 small rifle primers (in the absence of SP primers) and 5g of 231 under a 180g. Winchester TC. Has anyone observed this type of thing before and is it an indication of over-pressure?
Historian
I just finishred cleaning and sorting some .40 S&W brass that I fired at the range today. As I was sorting it, I noticed that there was an unusual raised area around the strike dimple. Under a magnifying glass, it became clear that this area was formed by the primer pressing on the firing pin hole. The outline of the firing pin hole from my M&P was clearly imprinted on the spent primer. I immediately began to wonder if these loads were too hot. I used CCI 400 small rifle primers (in the absence of SP primers) and 5g of 231 under a 180g. Winchester TC. Has anyone observed this type of thing before and is it an indication of over-pressure?
Historian
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