358156 hp
At large, whereabouts unknown.
I felt the need to see just how well I could uniform a mess of once-fired Federal 9mm cases, all from the same lot. I first dry tumbled them in my elderly Lyman tumbler, them sized & decapped them in preparation for a trip through the wet tumbler with stainless pins. All was well, and I ran them for a few hours until thoroughly clean. I planned to do some weight sorting, and wanted them as clean as possible for this. All went well, and then I inspected my cases as I fiddled with them.
One of the first things I noticed was that the flash holes seemed on the small size, I didn't think too much about it because case manufacturers seem to fiddle with such details at random. Then I found a few cases that were almost blocked completely. The flash hole from the primer pocket side appeared to be larger than it did from the case mouth side. All the cases were like this, so I checked a few other caliber cases that were cleaned and ready to load and noticed the same thing there too. It took me a minute, but I realized that tumbling the cases in stainless must be peening the burr around the flash hole flat, and that was causing the constriction.
I'm sure the cases would still fire, but I dug out my deburring tool and cleaned up all the cases I found like this, which was pretty much all of them. I can't help but wonder if this could be causing some match shooters some real variations in ES on their chronographs. I just thought I'd mention it. I'll still keep wet tumbling, but now everything will get the flash hole uniformed and deburred too. Weird, huh?
One of the first things I noticed was that the flash holes seemed on the small size, I didn't think too much about it because case manufacturers seem to fiddle with such details at random. Then I found a few cases that were almost blocked completely. The flash hole from the primer pocket side appeared to be larger than it did from the case mouth side. All the cases were like this, so I checked a few other caliber cases that were cleaned and ready to load and noticed the same thing there too. It took me a minute, but I realized that tumbling the cases in stainless must be peening the burr around the flash hole flat, and that was causing the constriction.
I'm sure the cases would still fire, but I dug out my deburring tool and cleaned up all the cases I found like this, which was pretty much all of them. I can't help but wonder if this could be causing some match shooters some real variations in ES on their chronographs. I just thought I'd mention it. I'll still keep wet tumbling, but now everything will get the flash hole uniformed and deburred too. Weird, huh?