I'm an Excel geek amongst other things, and after looking at a lot of pet load data, I started to see a pattern of favored bullet weights by cartridge. I spent a few hours trying to make some sense of all of the factors in Excel and this is the table I came up with. The result of the calculations is the "Opt. Wgt in gr...." Which according to the calculations, would be the most effective bullet for that particular chambering.

The Taylor Bekker Index at the end is just something I devised as an amalgamation of the two major schools of thought on knock down power. (if you believe in that sort of thing)

But I'll save that for another day.

Anyway here's the table, I'd be very interested in hearing your thoughts.

Very interesting - thank you for the work and for posting.

I have been woking along these thought lines as well. Dreamt up a table just setting SD and calculating the corensponding bullet weight for each caliber.



Goal was to have a start selecting "class" of bullet for comparison porposes between calibers.

Looking at your chart, SD 0,22 (calculated by metric) seems in most cases to be favoured.

This is interesting - as many years ago a trend was much more to heavy for caliber bullets. This trend continues in the +375 group accourding to your table.

I would like to know, what parameters you take to rule the bullet weight to be the most effective for a chambering - energy, momentum, powder used / fps...

The TBI is as flawed as similar indices as on game performance is much dependent on variables not factored in as location of the wound and wounded organs, psychological state of target animal...

Good work - looking forward to more and some discussion.

In the brief play with numbers before I started writing formulas, I found that caliber alone accounts for about 85% of optimum bullet weight. Mostly because I wanted to keep SD over .24 (English units)

In the calculations I had a threshold value of .23 SD.
Then using case capacity, bore volume (assuming equal length barrels), cross sectional area, and potential energy, I calculated the additional bullet weight to achieve optimum momentum. This tends to select for bullets with lower ballistics coefficients than the max recommended but does allow for better delivery of energy throughout the range of efficacy.

There are some errors in my math up there (typos of actual caliber values.) I have fixed them since.

I don't think there will ever be a truly good index of bullet performance for the very reasons that you list especially given that there is so much variety in bullets and infinite variety in bullet placement.

However, given the same test media and using cast lead bullets, it is an excellent indicator of penetration depth and channel diameter.