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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
VLD Bullets - How much should MV increase?
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<blockquote data-quote="Cybra" data-source="post: 24544" data-attributes="member: 936"><p>Ok, lets see...</p><p></p><p>You know, the funny thing with this is that different powders will really play a major role here. For example, by nitration content, a lot of VV's powders are very clean burning, and ignite efficiently, often completely converting from solid to gas in half the time/pressure ratio that different powders of similar speeds will. Another route to explanation; if you use a very slow burner, such as...H870, Retumbo, 5010...you would notice a LOT more velocity drop for those four inches, especailly with a bullet of that weight, and also because the shank length is quite short &lt;minimum bullet-bore friction&gt;. The bottom line is it is hard to approximate right to the last fps because of all the variables. </p><p></p><p>Here's what I found; assuming you were using H870 &lt;I don't know what YOU were using, but H870 was a powder I found would work, and would match up with the pressure/velocity situ. rather nicely&gt; with a 30" tube and 156gr projectile, I snarffed up some figures that got me to 3450fps. Chop 4" off, the speed drops to about 3320fps. BUT!--remember, the type of powder used will likely have the biggest effect--a faster burning powder will show less of a decrease, presumably. My earlier guess was based on RE25 for powder. I'd say you should be above 3300, anyhow. I used 3450 as you indicated that to be the accurate load, and for me, if it isn't accurate, it isn't worth a d*mn! </p><p></p><p>Dave <img src="http://images/icons/wink.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p></blockquote><p></p>
[QUOTE="Cybra, post: 24544, member: 936"] Ok, lets see... You know, the funny thing with this is that different powders will really play a major role here. For example, by nitration content, a lot of VV's powders are very clean burning, and ignite efficiently, often completely converting from solid to gas in half the time/pressure ratio that different powders of similar speeds will. Another route to explanation; if you use a very slow burner, such as...H870, Retumbo, 5010...you would notice a LOT more velocity drop for those four inches, especailly with a bullet of that weight, and also because the shank length is quite short <minimum bullet-bore friction>. The bottom line is it is hard to approximate right to the last fps because of all the variables. Here's what I found; assuming you were using H870 <I don't know what YOU were using, but H870 was a powder I found would work, and would match up with the pressure/velocity situ. rather nicely> with a 30" tube and 156gr projectile, I snarffed up some figures that got me to 3450fps. Chop 4" off, the speed drops to about 3320fps. BUT!--remember, the type of powder used will likely have the biggest effect--a faster burning powder will show less of a decrease, presumably. My earlier guess was based on RE25 for powder. I'd say you should be above 3300, anyhow. I used 3450 as you indicated that to be the accurate load, and for me, if it isn't accurate, it isn't worth a d*mn! Dave [img]images/icons/wink.gif[/img] [/QUOTE]
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VLD Bullets - How much should MV increase?
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