First, I want to thank the forum for allowing me to dominate the latter part of this thread with my attack on sectional density (SD) as an important hunting bullet consideration. This is a great forum of folks and I appreciate how we are able to keep (most) discussions civil, educational, and entertaining.
Second, I want to address
@Beck's OP questioning DD's opinion of SD. To this point, I had only watched the first few minutes of the video where he initially dismissed SD because I agreed 100% with that assessment. All my posts have been based on my own knowledge and understanding of math, ballistics, bullet design, and marketing. I just watched the complete video and can say that DD is 100% correct in everything he said. DD said one purpose of the video was to, "break you from the shackles of SD"; I agree that shooters and hunters should dismiss SD completely. He said something else that I will need to research for myself, but I believe him: "Sectional density was developed to optimize military artillery, not to describe a hunting bullet."
For fun, I put together a spreadsheet for your consideration. If you had to guess what the average SD is for the weight and primary caliber of every PG/DG hunting diameter (0.257 - 0.577), what would you guess? What if I told you it was 0.305? Would it be a surprise if I told you that the SD of the 375 H&H 300gr bullet was 0.305? There must be something special about mediocrity... I mean about being in the middle. Consider the following table:
View attachment 748864
The first column is obviously bullet diameter. I've presented a representative caliber because I was going to calculate loads that might equalize the energy between the calibers, but I got tired. The third column is important; it takes the SD of 0.305 for the 300gr 375 H&H and outputs the exact bullet weight every other caliber would need to be to give the same SD of 0.305. For better or worse, we live in an imperfect world, so we don't have bullets available to us in those exact weights. The next column shows what the typical or closest bullet weight is for each caliber and then the actual SD is calculated for that weight in the next column. Finally, the deviation from 0.305 is shown in the final column.
Everyone is free to draw their own conclusions; I merely present the data for entertainment purposes. I will point out a couple of comparisons for fun. The 7x57 Mauser may be capable of better penetration than the 375 H&H. Is the hunter going to choose the Mauser for buffalo or is he going to choose it as an alternative to the 375 for sable or impala? On the opposite scale, should the 505 Gibbs owner leave his rifle at home and instead rent the PH's 375 for elephant?
As another aside, I was reading through Hornady's 11th edition in preparation for my earlier posts in this thread. I just looked through again at their detailed bullet descriptions (they are a bullet manufacturer and retailer) and not once did they mention sectional density (SD). They mentioned ballistic coefficient (BC) many times, but not SD. Sectional density does not matter; it's not made up, but for the hunter it IS made up. It is of no consequence. It is easy to select the right bullet for the task at hand without ever thinking about sectional density. Heavier animals require heavier bullets that hold together on impact. Lighter animals may require bullets that fragment on impact. Sectional density is not going to advise you on the correct bullet to select for the animal you wish to fe example now.
