I was cleaning several thousand 45 ACP cases today. The cases were a mixed lot of Federal, Winchester and, Remington.
As I pushed the cleaning media from the primer flash holes, I noticed that some flash holes were noticeably larger than others. I sorted 10 of them into large and small hole groups and using drill bits and a micrometer, I measured the hole diameter.
The Winchester and Remington case's holes measured 0.075".
The Federal case's holes measured 0.095", or 0.020" larger.
I assumed that SAAMI-adopted standardized specifications would cover flash holes. Can anyone shed some light on this?
With a larger flash hole, would the effect of the larger hole on the flash reaching the powder be different? What might be the effect on pressure?
