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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Berger 215 twist rate??
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<blockquote data-quote="SnowbirdUT" data-source="post: 1780110" data-attributes="member: 88029"><p>I have read a number of books on this topic and took Bryan Litz 3 days class. </p><p></p><p>It is very hard to "over stabilize a bullet". In one of Litz's books he calculates the reduction in MV for each 1" increase in spin. It is Newtonian mechanics. If you increase the angular velocity (spin) that consumes energy which is observed as a reduction in MV. I don't remember the calculation exactly but a 1" increase in twist reduces MV by less that a few feet per second. Less than the typical SD with hand loads. </p><p></p><p>I use the Miller spin calculator published by Berger. Here it is. </p><p></p><p><a href="https://bergerbullets.com/twist-rate-calculator/" target="_blank">https://bergerbullets.com/twist-rate-calculator/</a></p><p></p><p>When figuring out the twist rate for a new barrel, I input the heaviest bullet I can shoot and I assume I am shooting at sea level. I then add .5" to 1" additional twist particularly if I intend to shoot through transonic. </p><p></p><p>No real loss of MV and I can stabilize the heaviest bullet I will use at any altitude.</p></blockquote><p></p>
[QUOTE="SnowbirdUT, post: 1780110, member: 88029"] I have read a number of books on this topic and took Bryan Litz 3 days class. It is very hard to “over stabilize a bullet”. In one of Litz’s books he calculates the reduction in MV for each 1” increase in spin. It is Newtonian mechanics. If you increase the angular velocity (spin) that consumes energy which is observed as a reduction in MV. I don’t remember the calculation exactly but a 1” increase in twist reduces MV by less that a few feet per second. Less than the typical SD with hand loads. I use the Miller spin calculator published by Berger. Here it is. [URL]https://bergerbullets.com/twist-rate-calculator/[/URL] When figuring out the twist rate for a new barrel, I input the heaviest bullet I can shoot and I assume I am shooting at sea level. I then add .5” to 1” additional twist particularly if I intend to shoot through transonic. No real loss of MV and I can stabilize the heaviest bullet I will use at any altitude. [/QUOTE]
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Berger 215 twist rate??
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