There are many good caliber and cartridge choices for handgun hunting, what you hunt will determine the best cartridge for you or your hunting situation. Here are a few of my own thoughts on handgun hunting situations.
Squirrel hunting with a handgun can be quite challenging and a lot of fun, the 22 magnum cartridge offers plenty for squirrel hunting and with the right ammunition a handgun chambered in 22 mag can be quite a handy piece for the home defense department.
Coyote hunting with a handgun is an interesting proposition as well, need practice time with your 9mm luger chambered pistol, coyote hunting can be fast and furious at times so a good semi-automatic pistol can be quite handy and once again loaded with the right ammunition you have home defense covered quite well with the 9mm. luger cartridge.
Javelina and pig hunting, here is a situation that really does make sense to carry a handgun and fast handling carbine rifle chambered in the same caliber and the caliber that comes to mind first is the good ol .357 magnum, these days many places in the south are now over-run with pigs. The 357 magnum carbine with 18 inch barrel has more bullet energy at 100 yards than a 8 inch barreled 357 magnum handgun has at the muzzle with the same cartridge load.
White-tailed deer hunting, it is recognized that many, many deer have been shot with less powerful handgun calibers, but to be consistent, most experts do agree that the .41 magnum is the minimum caliber to be used on whitetail, the .44 magnum is my personal choice. When hunting very thick cover a carbine rifle chambered in .44 magnum is quite handy for the occasional open area where you may have to shoot out too a hundred yards or so. The 44 magnum carbine with 18 inch barrel has more bullet energy at 100 yards than a 8 inch barreled 44 magnum handgun has at the muzzle with the same cartridge load.
Hornady Index of Terminal Standards:
(H.I.T.S.) is intended as a guideline to help hunters compare cartridge and bullet combinations. The index considers variables such as impact velocity, ballistic coefficient, sectional density and bullet weight. Bullet construction is another important factor in determining the best combination for your hunting situation.
Note: This is a guide for maximum handgun hunting effectiveness.
Based on creating a massive wound channel for quick one shot kills.
Less than 500 H.I.T.S.
The basic rule of thumb is that a H.I.T.S. rating of 500 or below describes a bullet/cartridge combination best suited for small game animals weighing less than 50 pounds.
A rating of 501 to 900 applies to bullet/cartridge combinations that are applicable for medium-sized game such as deer, antelope, black bear, and caribou, or game weighing 50 to 300 pounds.
A rating of 901 to 1,500 specifies cartridge/bullet combinations well-suited for large and heavy, but not generally considered dangerous game. This includes elk, moose, African plains game, red stag, American bison, and other animals weighing between 300 to 2,000 pounds.