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Rifles, Reloading, Optics, Equipment
Reloading
Why Now....higher pressures
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<blockquote data-quote="shaughn" data-source="post: 1241679"><p>45-70 has 3 power levels...Mostly....BP load pressure for vintage rifles and replica's...Intermediate for Certain lever actions and near 458 magnum load pressure for Ruger 1 and Siamese Mauser Bolt action to just name a few. Certain rifles both new and old can straddle the lines somewhat, hence the multiple load tables found in some reloading manuals.</p><p></p><p>The biggest reason is that there was/is a ongoing switch from Copper Units of pressure (CUP) ( which measured how much a copper cylinder was compressed in a special chamber upon firing the test round) to the Piezoelectric force sensor and strain gauges to determine pressure PSI (all have advantages/disadvantages). </p><p></p><p>There is not a direct translation or equivalent factor between CUP and PSI and I have known many people who have mixed and matched terminology over the years and not just average reloaders and hunters but some brainy people as well.</p><p></p><p>So with most of the manuals now measuring in PSI versus CUP, the old 50,000 CUP is more likely to be 65,000 +- PSI (random numbers).</p><p></p><p>Basically what you are seeing is the result of a change in the way they are measuring pressure, not that they are increasing pressure maximums, if anything I believe they are throttling back on some of them because modern testing has revealed that they might be closer to the ragged edge than they believed previously and the modern powders themselves are getting more done with less, which also causes changes.</p></blockquote><p></p>
[QUOTE="shaughn, post: 1241679"] 45-70 has 3 power levels...Mostly....BP load pressure for vintage rifles and replica's...Intermediate for Certain lever actions and near 458 magnum load pressure for Ruger 1 and Siamese Mauser Bolt action to just name a few. Certain rifles both new and old can straddle the lines somewhat, hence the multiple load tables found in some reloading manuals. The biggest reason is that there was/is a ongoing switch from Copper Units of pressure (CUP) ( which measured how much a copper cylinder was compressed in a special chamber upon firing the test round) to the Piezoelectric force sensor and strain gauges to determine pressure PSI (all have advantages/disadvantages). There is not a direct translation or equivalent factor between CUP and PSI and I have known many people who have mixed and matched terminology over the years and not just average reloaders and hunters but some brainy people as well. So with most of the manuals now measuring in PSI versus CUP, the old 50,000 CUP is more likely to be 65,000 +- PSI (random numbers). Basically what you are seeing is the result of a change in the way they are measuring pressure, not that they are increasing pressure maximums, if anything I believe they are throttling back on some of them because modern testing has revealed that they might be closer to the ragged edge than they believed previously and the modern powders themselves are getting more done with less, which also causes changes. [/QUOTE]
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Why Now....higher pressures
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