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Rifles, Reloading, Optics, Equipment
Reloading
Are your flash holes centered?
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<blockquote data-quote="nheninge" data-source="post: 485456" data-attributes="member: 13085"><p>Well I repeated some of my tests and get similar data, but not sure exactly what it means... </p><p></p><p>1) Is the flash hole off center from the axis of the cartridge with concentric primer pocket?</p><p></p><p>2) Is the primer pocket off center w/ the flash hole in the middle of the primer pocket</p><p></p><p>3) Are other contributing factors adding to the runout giving a false reading</p><p></p><p>I get runout on both new and once fired brass. I feel that most likely primer pockets are concentric, and that the error comes from drilling/punching flash holes slightly off center, with some being noticeably off center. If the flash hole is not in the middle of the pocket than it would likely impact the direction/concentration of the flame to some degree. Add that to a horizontal non-compressed load...?</p><p></p><p>My theory is to sort my brass initially on neck thickness variation, that way I can eliminate the banana cartridge theory. If the brass is the same all the way down, it can't form a banana. My data says that neck thickness variation continues down the length of the case. Spinning cases on a homemade guage with a feeler bar at the case web showed runout there as well. This was not as present in cases with minimal neck thickness variation. If I am shooting cases with neck thickness variation I always index. It is really easy to do. Just give a light neck turn and the side of the neck that isn't trimmed is the thin side! Then mark with a small file. Cases with increased neck variation after neck turning actually increase bullet/neck runout until after the first fireforming.</p><p></p><p>I have ordered 100 win brass to get (just barely) 50 pieces of usable brass. Good brass (norma/lapua) just cuts down on my work and worry. I can make rem/win/fed brass good, but it takes A LOT more effort. Now add in the flash hole sort, maybe I'd need 150? All of the sudden, Norma brass isn't so expensive.</p><p></p><p>My thoughts are initially to spin the cases and catch the flash holes that are really off and cull. Where to make the cut will have to be empirical without field trials for now. Simple, easy and effective. Spin once and done and on to the range.</p></blockquote><p></p>
[QUOTE="nheninge, post: 485456, member: 13085"] Well I repeated some of my tests and get similar data, but not sure exactly what it means... 1) Is the flash hole off center from the axis of the cartridge with concentric primer pocket? 2) Is the primer pocket off center w/ the flash hole in the middle of the primer pocket 3) Are other contributing factors adding to the runout giving a false reading I get runout on both new and once fired brass. I feel that most likely primer pockets are concentric, and that the error comes from drilling/punching flash holes slightly off center, with some being noticeably off center. If the flash hole is not in the middle of the pocket than it would likely impact the direction/concentration of the flame to some degree. Add that to a horizontal non-compressed load...? My theory is to sort my brass initially on neck thickness variation, that way I can eliminate the banana cartridge theory. If the brass is the same all the way down, it can't form a banana. My data says that neck thickness variation continues down the length of the case. Spinning cases on a homemade guage with a feeler bar at the case web showed runout there as well. This was not as present in cases with minimal neck thickness variation. If I am shooting cases with neck thickness variation I always index. It is really easy to do. Just give a light neck turn and the side of the neck that isn't trimmed is the thin side! Then mark with a small file. Cases with increased neck variation after neck turning actually increase bullet/neck runout until after the first fireforming. I have ordered 100 win brass to get (just barely) 50 pieces of usable brass. Good brass (norma/lapua) just cuts down on my work and worry. I can make rem/win/fed brass good, but it takes A LOT more effort. Now add in the flash hole sort, maybe I'd need 150? All of the sudden, Norma brass isn't so expensive. My thoughts are initially to spin the cases and catch the flash holes that are really off and cull. Where to make the cut will have to be empirical without field trials for now. Simple, easy and effective. Spin once and done and on to the range. [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Reloading
Are your flash holes centered?
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