The Calculator

I have always liked the bigbore guns in both handgun and rifles. I heard or read a good advice once, for hunting, take the biggest gun you are able to shoot with confidence whatever the size of the animal.

If you don’t like bigbore (read hard recoiling guns) then don’t go after big game. There are lots of “rules” to follow, some of them from the law in that place you hunt, some of them good advice from people who put down a lots of animals.
One of them is John Taylor. He developed a formula called KO that gives you a number of the killing power of your cartridge/bullet combination. It’s mainly used for bigbores and hunting big game in Africa.

SD stands for Sectional Density and it’s as important to hunting bullets as BC (Ballistic Coefficient) is for target long range shooting. Better Sd means better penetration to the vital organs of the animal. SD is the correlation number between the weight and the calibre of your bullet

Momentum is the "pushing" power of your bullet, higher is better. The big difference between Momentum and Kinetic energy is that momentum is the 18 wheeler that drives over you and the Kinetic energy more like a Formula 1 car :)

For small animals I will try to get as much Kinetic energy as possible but for big ones I stick to the momentum numbers.

Another expert in that field is Ed Matunas and his OGW (Optimal Game Weight) formula gives you the weight that your cartridge bullet is capable of taking down, if used properly.
You have both Varmint type bullets OGW and Big Game OGW below.

The Recoil numbers are here just for comparing different guns and loads. Bigger bullets, higher velocity and light guns give you more recoil, nothing strange about it.