Mitdr774 Wrote:SD might be a function of weight and diameter, but as you go up in diameter you also loose length for the same given weight. While length may not be part of the math equation to figure out SD, it is something that is involved in the final product. Given the same construction and design, a long "heavy" 6mm will have a better SD than a short "lightweight" 6.5mm if they are both the same weight. This long and heavy for caliber should also result in a better BC.
Nosler Partition 100gr (all numbers sourced from Midway)
.243" SD of .242, 1.065" length, G1 BC .384
.257" SD of .216, 1.035" length, G1 BC .377
.264" SD of .205, 0.962" length, G1 BC .326
Not sure what your trying to illustrate with those numbers sourced from Midway. No one said higher SD bullets cant be longer, Im saying length is not the reason why they have a higher SD, thats all.
How do you reconcile this? Compare two 90 grn 6mm bullets. One solid lead, the other solid copper. I think most would agree the solid copper bullet would then have to be much longer because, copper is less dense than lead. Right? Yet both would still have the exact same SD. And the solid copper bullet, all things being equal, could also have a much higher BC, yet the same SD.