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Rifles, Reloading, Optics, Equipment
Reloading
Case weight variability question
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<blockquote data-quote="Mikecr" data-source="post: 2193078" data-attributes="member: 1521"><p>Each system (brass alloy, cartridge design, chamber clearances, load) will exhibit it's own character.</p><p>Lapua 6BR tight -vs- Norma 30-06 loose,, the numbers are all different. And these are different than your STW/WSM/WM volumes and designs.</p><p></p><p>What makes the Ackley improved designs so much easier to manage here is the use of lower body taper/higher shoulder angles and shorter cases per capacities. They need less sizing, so the cases stay more consistent in hardness and springbacks, and volumes.</p><p>In the long run they truly are improvements.</p><p></p><p>FL sizing serves to reduce dimensions, easier chambering, but it cannot undo the changes occurring to brass character.</p><p>Once you've yielded brass, it wants to go back to that new balance, It will go back there with less pressure. So people running high pressure loads end up with popping extraction even while FL sizing. They end up polishing out the breach or going ring die for webs.</p><p>The root cause of all this is high chamber clearances to begin.</p><p></p><p>With tighter clearances the brass changes less at given pressure levels. It can't change more because the chamber won't allow it.</p><p>That actually means less issue with extraction, because the brass doesn't go so deep into yielding where it would spring back less from chamber walls(potentially leaving interference fit). This is also why it's important to have enough barrel steel around the chamber, and strongest breech support possible(so the chamber does not expand excessively).</p><p>Tighter clearances are not a problem load-wise, as you develop loads with it.</p><p>That's why it's important to fire form cases to stable(per your reloading plan) -before load development.</p><p></p><p>Take new brass to it's new form & character, and THEN work with that. Go ahead and plan for it right up front.</p></blockquote><p></p>
[QUOTE="Mikecr, post: 2193078, member: 1521"] Each system (brass alloy, cartridge design, chamber clearances, load) will exhibit it's own character. Lapua 6BR tight -vs- Norma 30-06 loose,, the numbers are all different. And these are different than your STW/WSM/WM volumes and designs. What makes the Ackley improved designs so much easier to manage here is the use of lower body taper/higher shoulder angles and shorter cases per capacities. They need less sizing, so the cases stay more consistent in hardness and springbacks, and volumes. In the long run they truly are improvements. FL sizing serves to reduce dimensions, easier chambering, but it cannot undo the changes occurring to brass character. Once you've yielded brass, it wants to go back to that new balance, It will go back there with less pressure. So people running high pressure loads end up with popping extraction even while FL sizing. They end up polishing out the breach or going ring die for webs. The root cause of all this is high chamber clearances to begin. With tighter clearances the brass changes less at given pressure levels. It can't change more because the chamber won't allow it. That actually means less issue with extraction, because the brass doesn't go so deep into yielding where it would spring back less from chamber walls(potentially leaving interference fit). This is also why it's important to have enough barrel steel around the chamber, and strongest breech support possible(so the chamber does not expand excessively). Tighter clearances are not a problem load-wise, as you develop loads with it. That's why it's important to fire form cases to stable(per your reloading plan) -before load development. Take new brass to it's new form & character, and THEN work with that. Go ahead and plan for it right up front. [/QUOTE]
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Case weight variability question
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