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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
375/408 Banded Solids Test
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<blockquote data-quote="noel carlson" data-source="post: 901478" data-attributes="member: 16138"><p>"Maybe you are including the bore rider in front... "...</p><p></p><p>Yes, I am. From an aero-ballistic standpoint there is no difference. </p><p></p><p>Ability to overcome wave-drag comes from ogive length (primarily), and ogive form (secondarily). There is no aerodynamic efficiency "credit" for a long projectile body, only potential "debits". Rifling engraving, engraving bands, pressure relief grooves, cannelures, etc. all contribute significantly to parasitic drag. You need to visualize a projectile shaft that has passed through rifling when estimating the drag penalty. At best, only smooth-surface drag will be present.</p><p></p><p>Mechanically, the bearing surface needs to be >1 1/2 calibers in length. Artillery shells typically have an ~2 caliber-long bearing surface. The practical requirements of mass on copper solids used in small arms is >2 calibers. The tail is between 1 caliber, and 1 1/2 calibers in length... as dictated by a boat-tail angle range between 7, and 9 degrees. The balance is left for nose length. </p><p></p><p>It is a balancing act.</p></blockquote><p></p>
[QUOTE="noel carlson, post: 901478, member: 16138"] "Maybe you are including the bore rider in front... "... Yes, I am. From an aero-ballistic standpoint there is no difference. Ability to overcome wave-drag comes from ogive length (primarily), and ogive form (secondarily). There is no aerodynamic efficiency "credit" for a long projectile body, only potential "debits". Rifling engraving, engraving bands, pressure relief grooves, cannelures, etc. all contribute significantly to parasitic drag. You need to visualize a projectile shaft that has passed through rifling when estimating the drag penalty. At best, only smooth-surface drag will be present. Mechanically, the bearing surface needs to be >1 1/2 calibers in length. Artillery shells typically have an ~2 caliber-long bearing surface. The practical requirements of mass on copper solids used in small arms is >2 calibers. The tail is between 1 caliber, and 1 1/2 calibers in length... as dictated by a boat-tail angle range between 7, and 9 degrees. The balance is left for nose length. It is a balancing act. [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
375/408 Banded Solids Test
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