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Rifles, Reloading, Optics, Equipment
Reloading
TIGHTEN PRIMER POCKETS, here's how.
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<blockquote data-quote="Pdvdh" data-source="post: 1219840" data-attributes="member: 4191"><p>The 1/4" grade 8 bolt I initially attempted to use, without modification, could never have worked for me. I have that bolt and my calipers in my hands now. The diameter of the bolt is 0.245" on both the solid and threaded section of the bolt. However, the end of that bolt cones down to 0.178" diameter. Which means I was hitting the back side of 0.211" diameter primer pockets with a grade 8 bolt that only measured 0.178" diameter. Duh! At least I learned that lesson after damaging only the initial Lapua 30-06 casing.</p><p></p><p>If I cut the threads off the 1/4" bolt shank then the diameter of the bolt would be a full 0.245". That might work, but that still only leaves ~0.017" to spare on all sides of the primer pocket, if the bolt is centrally positioned over the primer pocket.</p><p></p><p>The 5/16" diameter bolt I ground down to clear the case necks originally had a shank diameter of 0.307". After grinding and reducing the shank diameter to clear the necks of my .280 RCBS Improved casings, the diameter of the end of the bolt that impacts the back side of the primer pockets measures 0.264". So I gained ~0.019", and that bolt now overlaps the primer pockets by 0.026" on all sides if centrally positioned over the primer pocket. And that bolt works just fine, without damaging the primer pockets.</p><p></p><p>I may grind another 5/16" bolt down and proceed more carefully, as a 0.280" diameter bolt should clear the necks on my fired 280 cases. If I had a lathe and the precision-enabling tools of a machine shop, I'd turn them down more precisely to maintain maximum shank diameter.</p></blockquote><p></p>
[QUOTE="Pdvdh, post: 1219840, member: 4191"] The 1/4" grade 8 bolt I initially attempted to use, without modification, could never have worked for me. I have that bolt and my calipers in my hands now. The diameter of the bolt is 0.245" on both the solid and threaded section of the bolt. However, the end of that bolt cones down to 0.178" diameter. Which means I was hitting the back side of 0.211" diameter primer pockets with a grade 8 bolt that only measured 0.178" diameter. Duh! At least I learned that lesson after damaging only the initial Lapua 30-06 casing. If I cut the threads off the 1/4" bolt shank then the diameter of the bolt would be a full 0.245". That might work, but that still only leaves ~0.017" to spare on all sides of the primer pocket, if the bolt is centrally positioned over the primer pocket. The 5/16" diameter bolt I ground down to clear the case necks originally had a shank diameter of 0.307". After grinding and reducing the shank diameter to clear the necks of my .280 RCBS Improved casings, the diameter of the end of the bolt that impacts the back side of the primer pockets measures 0.264". So I gained ~0.019", and that bolt now overlaps the primer pockets by 0.026" on all sides if centrally positioned over the primer pocket. And that bolt works just fine, without damaging the primer pockets. I may grind another 5/16" bolt down and proceed more carefully, as a 0.280" diameter bolt should clear the necks on my fired 280 cases. If I had a lathe and the precision-enabling tools of a machine shop, I'd turn them down more precisely to maintain maximum shank diameter. [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Reloading
TIGHTEN PRIMER POCKETS, here's how.
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