The flash hole: A reloader walks up to a case, turns it over and then measures the flash hole, the diameter of the flash hole is .085”, then what? A conclusion is dawned by the reloader? That is not possible, because, the reolader did not know the diameter of the flash hole when the case was manufactured, back to measuring before and again after. A reloader fired one 308 Winchester case 47 times, I ask him the weight of the case before he started, he did not know (the weight) and he did not know why I ask the question, I did not get around to asking him the diameter of the flash hole through 47 firings, I did not ask him the diameter of the case head before and again after the test? I did not ask him the case head thickness before and again after he started his test.
I do not measure the diameter of the flash hole for the sake of knowing the diameter of the flash hole, but when I do measure the flash hole expect the diameter of the flash hole to increase in diameter the next time it is fired. One member on this forum drills his flash holes to a uniform diameter, first reason: JIC, just in case it matters. then there is the effect pressure has on the case when fired. Always the primer, get ‘tuffer’ primers, I read that a lot, if pressure has an effect on a case every part of the case is effected starting with the flash hole, I have cases with flash holes that were rendered scrap in one firing, the rendering to scrap was not confined to the flash hole, the head of the cases were crushed, the diameter of the primer pocket would not hold a shot gun primer, the case head thickness decreased, the primer? The first sign of an indication there was/is a problem with pressure? I did not find them until I took the rifles apart, sure enough, the primer showed signs of pressure. I was told the receivers were suspect. seems the receivers started out as 7MM57s and were converted to 30/06, the 30/06 barrels were shot out and one still the case in the chamber less the case head. the suggestion was to use the barrels as tomato stakes??? I purchased 4 rifles for $25.00 each, that means nothing to the tomato ‘stake-rs’ but for me? I cut the chamber off of the barrel and make ‘instant’ chamber gages, real chamber gages, not the chamber gages sold on the Internet that are poor copies of the L.E. Wilson case gage.
I got a deal on LC MATCH 30/06 cases, .08 cents each, the flash holes were not in the center, I thought I had purchased a life time supply, not so, seems I was supposed to call friends and ask if they wanted a few, I called Pat in Ohio, he made me a deal on on more cases plus shipping (very reasonable), I ordered another 4,000 cases. When it comes to case forming there is nothing like starting with a new unfired case, and, the ideal a case will not cost me more than .08 cents each plus my time.