KO factor multiplies bullet weight (measured in grains) by muzzle velocity (measured in feet per second) by bullet diameter (measured in inches) and then divides the product by 7,000, converting the value from grains to pounds and giving a numerical value from 0 to ~150 for normal hunting cartridges. Expressed as a fraction, the Taylor KO Factor is: |
For hunting elephants, a Taylor Knock-Out (TKO) factor of at least 40 is generally considered the minimum for a reliable and effective kill. However, it's important to understand that TKO factor is a measure of a cartridge's ability to cause concussion and incapacitation, and while a high TKO factor is desirable, it doesn't guarantee a clean, humane kill.
I have never hunted an elephant, but like the study and science & debate this topic seems to bring.
I would say that I would be comfortable with a .40 cal + , when dealing with a hippopotamus or elephant