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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Drag Function question.
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<blockquote data-quote="JBM" data-source="post: 32244" data-attributes="member: 1969"><p><BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR> Ok so let me see if I got this strait. Say I load up a 142 grain 6.5MM SMK. I'd use the G1 Function. For a 140G Burger VLD I'd use the G7 function and a 140g AMAX I'd use the G5?<HR></BLOCKQUOTE></p><p></p><p>The short answer is that you use the G function for which you have ballistic coefficients. If you have a G1 BC for the VLD you have to use the G1 drag function otherwise any trajectory you calculate is wrong.</p><p></p><p>I've not seen anything except G1 BCs from Sierra so you'd always use a G1 drag function from them. The BC on Bergers site for the 140 grain VLD looks like a G1 BC so you'd use a G1 drag function there too -- same for the AMAX.</p><p></p><p>Most, if not all manufacturers provide G1 BCs so use the G1 curve.</p></blockquote><p></p>
[QUOTE="JBM, post: 32244, member: 1969"] <BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR> Ok so let me see if I got this strait. Say I load up a 142 grain 6.5MM SMK. I'd use the G1 Function. For a 140G Burger VLD I'd use the G7 function and a 140g AMAX I'd use the G5?<HR></BLOCKQUOTE> The short answer is that you use the G function for which you have ballistic coefficients. If you have a G1 BC for the VLD you have to use the G1 drag function otherwise any trajectory you calculate is wrong. I've not seen anything except G1 BCs from Sierra so you'd always use a G1 drag function from them. The BC on Bergers site for the 140 grain VLD looks like a G1 BC so you'd use a G1 drag function there too -- same for the AMAX. Most, if not all manufacturers provide G1 BCs so use the G1 curve. [/QUOTE]
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Rifles, Bullets, Barrels & Ballistics
Drag Function question.
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