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Rifles, Reloading, Optics, Equipment
Reloading
Overpressure Signs ?
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<blockquote data-quote="Clark" data-source="post: 229172" data-attributes="member: 6600"><p>I have overloaded to case failure with 22-250, .243, .243Win, 257 Roberts AI, 270, 7x57mm, .308, 30-06, and 8x57mm.</p><p></p><p>Most of these cartridges have different max pressures ranging from 37kcup to 65kpsi per SAAMI registration in the USA, but they all have the same real pressure limitations in modern strong bolt actions.</p><p></p><p>These cartridges and many more descended from the 1889 parent cartridge: 7.65x53mm Mauser.</p><p></p><p>If you are good with Quickload, and change the start pressure from 2,000 psi to 5,000 psi when the bullet is jammed into the lands, then a very accurate velocity and pressure prediction can be made.</p><p></p><p>The above Mauser case head cartridges, your 30-06 included, will have long brass life [the primer pockets will not get loose] at ~ 62,000 psi.</p><p></p><p>If you don't mind still bolt lift and loose primer pockets after one firing, you may shoot at 72,000 psi.</p><p></p><p>If you shoot at 90,000 psi, then the primer will fall out, and you have escaping gas on the bolt face.</p><p>I have overloaded lots of ammo until the primer pocket doubled in size, but that is not a useful practice toward practical ammo, other than a lesson in upper safety limits.</p><p></p><p>The exception to this is the 6mmBR and 6.5x47mm brass that has small rifle primer pockets.</p><p>The limitation to pressure with this case head [although shaped like an 1889 Mauser case head, it is much stronger] is the CCI450 magnum small rifle primer piercing. To get higher pressure, the firing pin should be bushed. If the firing pin is .062" and the firing pin hole is .063", then the pressure can go to the next level.</p></blockquote><p></p>
[QUOTE="Clark, post: 229172, member: 6600"] I have overloaded to case failure with 22-250, .243, .243Win, 257 Roberts AI, 270, 7x57mm, .308, 30-06, and 8x57mm. Most of these cartridges have different max pressures ranging from 37kcup to 65kpsi per SAAMI registration in the USA, but they all have the same real pressure limitations in modern strong bolt actions. These cartridges and many more descended from the 1889 parent cartridge: 7.65x53mm Mauser. If you are good with Quickload, and change the start pressure from 2,000 psi to 5,000 psi when the bullet is jammed into the lands, then a very accurate velocity and pressure prediction can be made. The above Mauser case head cartridges, your 30-06 included, will have long brass life [the primer pockets will not get loose] at ~ 62,000 psi. If you don't mind still bolt lift and loose primer pockets after one firing, you may shoot at 72,000 psi. If you shoot at 90,000 psi, then the primer will fall out, and you have escaping gas on the bolt face. I have overloaded lots of ammo until the primer pocket doubled in size, but that is not a useful practice toward practical ammo, other than a lesson in upper safety limits. The exception to this is the 6mmBR and 6.5x47mm brass that has small rifle primer pockets. The limitation to pressure with this case head [although shaped like an 1889 Mauser case head, it is much stronger] is the CCI450 magnum small rifle primer piercing. To get higher pressure, the firing pin should be bushed. If the firing pin is .062" and the firing pin hole is .063", then the pressure can go to the next level. [/QUOTE]
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