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Long Range Hunting & Shooting
Lead vs copper.
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<blockquote data-quote="Hugnot" data-source="post: 2379048" data-attributes="member: 115658"><p>I ran some Sg's on my spread sheet & came up with this:</p><p></p><p>[ATTACH=full]323459[/ATTACH]</p><p></p><p></p><p>This stuff shows the 165 Cutting Edge Lazer's Sg is sort of adequate at lower temps like when shooting deers & other. I would go for the shorter Cutting-Edge bullets. I selected the 168 Hornady ELDM as a sample comparison bullet because it is a cup/core, weighs 168 grains & has a plastic tip. A Sg of 1.4 has been defined as minimum for stability in Miller method Sg calculations. Berger might go higher at 1.5 for complete stability. The Berger Sg program does not make provisions for tipped bullets & uses altitude instead of actual pressure, the last time I ran it. Altitude values may not indicate actual atmospheric pressure. 2650 fps seems like a nice MV for a 168 out of a .308. Various manuals show MV's in the mid 2700 fps range for 165-168 bullets. This velocity increase would only show a tiny Sg increase as indicated by -(M375/2800) in the math, M375 being the velocity. This spread sheet calculation matches that of JBM's and if corrected for altitude matches Berger's. </p><p></p><p>If you have Apache Open Office software (free) on your computer this stuff can be duplicated. The math is shown on the top line. Lots of "( ), & exponential shown by "^". Picky but simple math.</p></blockquote><p></p>
[QUOTE="Hugnot, post: 2379048, member: 115658"] I ran some Sg's on my spread sheet & came up with this: [ATTACH type="full" alt="Screenshot (321).png"]323459[/ATTACH] This stuff shows the 165 Cutting Edge Lazer's Sg is sort of adequate at lower temps like when shooting deers & other. I would go for the shorter Cutting-Edge bullets. I selected the 168 Hornady ELDM as a sample comparison bullet because it is a cup/core, weighs 168 grains & has a plastic tip. A Sg of 1.4 has been defined as minimum for stability in Miller method Sg calculations. Berger might go higher at 1.5 for complete stability. The Berger Sg program does not make provisions for tipped bullets & uses altitude instead of actual pressure, the last time I ran it. Altitude values may not indicate actual atmospheric pressure. 2650 fps seems like a nice MV for a 168 out of a .308. Various manuals show MV's in the mid 2700 fps range for 165-168 bullets. This velocity increase would only show a tiny Sg increase as indicated by -(M375/2800) in the math, M375 being the velocity. This spread sheet calculation matches that of JBM's and if corrected for altitude matches Berger's. If you have Apache Open Office software (free) on your computer this stuff can be duplicated. The math is shown on the top line. Lots of "( ), & exponential shown by "^". Picky but simple math. [/QUOTE]
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