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Long Range Hunting & Shooting
The good, bad, ugly, and entertainment of "Crazy ideas"
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<blockquote data-quote="357Mag" data-source="post: 2404088" data-attributes="member: 106883"><p>Varmint Hunter + -</p><p></p><p>Howdy !</p><p></p><p>Yeh..... rifle' "expansion ratio " does " have something to do with it ".</p><p></p><p>Taking a causual look @ some smaller calibre wildcats based on .375 Rger brass:</p><p></p><p>Hodgon load data showed 87.4gr as the max powder charge of any powder under the lightest .375 bullet listed.</p><p>When necking down to a smaller cal, lighte weght bullets would invariably be utilized. And, as calibre goes down, chamber pressure would nominally go up.</p><p></p><p>Refering to an " expansion ratio " chart ballistician Homer Powley had printed in the Guns & Ammo 1974 Annual ":</p><p>- Powley's chart only listed a low expansion ratio ( inefficient case ) of 4, and a high end expansion ratio ( efficient case ) of 14; for various calibres from .20" to .50" . * He did not show expansion ratios lower than, most likely since any such cartridge would be grossly inefficient @ turning powder into velocity.</p><p></p><p>- When necking down the parent case.... even w/o any additional changes other than neck diam and neck lg,</p><p>smaller diameter versions of the wildcat(s) would have decreased case capacity.... when such capacity is measured using H2O added up till it reaches the case mouth. Therefore, smaller calibre itterations will have a somewhat smaller space for the powder charge, but not a whole bunch less than the original calibre case held.</p><p></p><p>Powley's chart was graphed using a notional 28" barrel lg for all calibres listed. Per the graph, a notional .224" cal wildcat that holds 72gr or powder would peg the expansion ratio @ 4. A postulated ." 22-375 Ruger " would </p><p>exceed 72gr of powder in capacity; and so would have an even worse expansion ratio than 4.</p><p></p><p>* In 6mm...... the powder capcity would have to be close to 88gr for an expansion ratio of 4 to be reached. </p><p>Therefore, if the barrel of the " 6-.375 Ruger " chambered rifle were shortened any, to 26", 24", etc' the expansion ratio would go lower than 4. And 4 isn't all that great a ratio to start with.</p><p></p><p></p><p>With regards,</p><p> 357Mag</p><p></p><p>holding</p></blockquote><p></p>
[QUOTE="357Mag, post: 2404088, member: 106883"] Varmint Hunter + - Howdy ! Yeh..... rifle' "expansion ratio " does " have something to do with it ". Taking a causual look @ some smaller calibre wildcats based on .375 Rger brass: Hodgon load data showed 87.4gr as the max powder charge of any powder under the lightest .375 bullet listed. When necking down to a smaller cal, lighte weght bullets would invariably be utilized. And, as calibre goes down, chamber pressure would nominally go up. Refering to an " expansion ratio " chart ballistician Homer Powley had printed in the Guns & Ammo 1974 Annual ": - Powley's chart only listed a low expansion ratio ( inefficient case ) of 4, and a high end expansion ratio ( efficient case ) of 14; for various calibres from .20" to .50" . * He did not show expansion ratios lower than, most likely since any such cartridge would be grossly inefficient @ turning powder into velocity. - When necking down the parent case.... even w/o any additional changes other than neck diam and neck lg, smaller diameter versions of the wildcat(s) would have decreased case capacity.... when such capacity is measured using H2O added up till it reaches the case mouth. Therefore, smaller calibre itterations will have a somewhat smaller space for the powder charge, but not a whole bunch less than the original calibre case held. Powley's chart was graphed using a notional 28" barrel lg for all calibres listed. Per the graph, a notional .224" cal wildcat that holds 72gr or powder would peg the expansion ratio @ 4. A postulated ." 22-375 Ruger " would exceed 72gr of powder in capacity; and so would have an even worse expansion ratio than 4. * In 6mm...... the powder capcity would have to be close to 88gr for an expansion ratio of 4 to be reached. Therefore, if the barrel of the " 6-.375 Ruger " chambered rifle were shortened any, to 26", 24", etc' the expansion ratio would go lower than 4. And 4 isn't all that great a ratio to start with. With regards, 357Mag holding [/QUOTE]
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