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Rifles, Reloading, Optics, Equipment
Reloading
Temperature sensitivity of US869
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<blockquote data-quote="CatShooter" data-source="post: 128566" data-attributes="member: 7"><p>[ QUOTE ]</p><p><strong>... The approach is not perfect (at 60 deg the air in the pipe will be denser) - denser air would lower the velocity even more (but probably less than 3%). What a great idea - work up a velocity/temp data chart. </strong></p><p></p><p>[/ QUOTE ]</p><p></p><p>Big Bore...</p><p></p><p>You have taken the art of silly to new, all time heights.</p><p></p><p>If you want to count the angels on the head of a pin, you must first know the size of their shoes, the size of their waist, and the size of their bra...</p><p></p><p>Air at 59 degrees "F" = 1.2 grams per liter (1000 cc) or 0.0012 grams per cc or 0.0185 grains per cc @59 degrees</p><p></p><p>At "0" degrees "F" - 0.0209 grains per cc</p><p></p><p>Volume... 1 cubic centimeter = 0.061 023 744 cubic inch</p><p></p><p>volume of .308x26" barrel = 0.6166 cubic inches</p><p></p><p>Therefore the weight of the air in a 30 cal barrel that is 26" long (NOT including the chamber) is 0.001128939819 grains at 59 degrees and 0.0012753968766 grains at "0" degrees, or a whoppin' 0.0001464570576 grain difference in the weight of the air in the barrel from 59 degrees to "0" degrees.</p><p></p><p>I think (in my humble opinion) that 0.000146 of a grain weight difference in the weight of the air in the barrel will not make a difference in the velocity... since it is about 1/1000th of the weight difference between bullets of the same lot number /ubbthreads/images/graemlins/wink.gif /ubbthreads/images/graemlins/wink.gif</p></blockquote><p></p>
[QUOTE="CatShooter, post: 128566, member: 7"] [ QUOTE ] [b]... The approach is not perfect (at 60 deg the air in the pipe will be denser) - denser air would lower the velocity even more (but probably less than 3%). What a great idea - work up a velocity/temp data chart. [/b] [/ QUOTE ] Big Bore... You have taken the art of silly to new, all time heights. If you want to count the angels on the head of a pin, you must first know the size of their shoes, the size of their waist, and the size of their bra... Air at 59 degrees "F" = 1.2 grams per liter (1000 cc) or 0.0012 grams per cc or 0.0185 grains per cc @59 degrees At "0" degrees "F" - 0.0209 grains per cc Volume... 1 cubic centimeter = 0.061 023 744 cubic inch volume of .308x26" barrel = 0.6166 cubic inches Therefore the weight of the air in a 30 cal barrel that is 26" long (NOT including the chamber) is 0.001128939819 grains at 59 degrees and 0.0012753968766 grains at "0" degrees, or a whoppin' 0.0001464570576 grain difference in the weight of the air in the barrel from 59 degrees to "0" degrees. I think (in my humble opinion) that 0.000146 of a grain weight difference in the weight of the air in the barrel will not make a difference in the velocity... since it is about 1/1000th of the weight difference between bullets of the same lot number [img]/ubbthreads/images/graemlins/wink.gif[/img] [img]/ubbthreads/images/graemlins/wink.gif[/img] [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Reloading
Temperature sensitivity of US869
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