This article is a guide to choosing at least a minimally appropriate rifle caliber/cartridge for hunting the three classes of big game animals. These are referred to as Class 2, Class 3 and Class 4. (Class 1 is small game and varmints.)

Class 2 refers to all thin-skinned, hoofed game averaging under about 300 pounds in live weight. In North America this includes the various deer species, pronghorn antelope, sheep, goats, caribou, black bear and feral hogs. It would also include most deer, antelope, sheep, goats and similar size animals around the world.

Class 3 refers to large, thin-skinned game averaging 300-2000 pounds live weight. These normally include North American elk, moose and musk ox, Scandinavian moose, European red stag, African kudu, oryx, eland and similar size game animals around the world. Very large black bear and very large European wild boar might also be included.

Class 4 represents thick-skinned, dangerous game and the large predators. There are no weight limits for Class 4 game. Examples of the former include American bison, Asian water buffalo, Cape buffalo, rhino, hippo and elephant. The latter include grizzly and brown bear, polar bear, jaguar, leopard, lion and tiger. Note that in most African countries the 9.3x62mm and/or .375 H&H are mandated by law as the minimum for hunting lion, Cape buffalo, rhino, hippo and elephant.

Mixing thick-skinned game with predators creates a sort of gray area. Clearly, a 150 pound leopard is a lot easier to dispatch than a 13,000 pound elephant. Probably, in most circumstances, the calibers and loads suitable for Class 3 animals are also suitable for hunting the dangerous predators. However, more powerful cartridges would be reassuring if it becomes necessary to track a lion or grizzly bear into thick cover!

The big predators (bears and cats) are probably best hunted with powerful rifles on the order of the .300 Magnums, 8mm Magnums, .338 Magnums, .35 Magnums, 9.3x62mm, 9.3x74R and .375 Magnums. However, the .30-06 and 7mm Magnums shooting heavy for caliber bullets are often used. In Alaska the Dept. of Fish and Game suggests the .30-06/220 grain load as the minimum for hunting brown bear.

Caliber (bullet diameter) is not an accurate indication of killing power, so alone it is not a reliable guide to cartridge selection. For example, the .375 Winchester is primarily a deer and black bear cartridge, while the .375 H&H Mag. is an international dangerous game cartridge.

Similarly, the .44-40 and .44 Remington Magnum are technically big bore cartridges, but they are Class 2 game calibers in terms of killing power. The .45-70 is a true big bore caliber and with heavy bullets and maximum loads it is suitable for all Class 3 class game, North American bison and the dangerous predators. However, it is not generally recommended for hunting the largest and most dangerous Class 4 game (Cape buffalo, rhino, hippo and elephant). The same applies to the .450 Marlin.

For the purposes of this article I will use Hornady H.I.T.S. (Hornady Index of Terminal Standards) as a guide to choosing acceptable cartridges for hunting the three classes of big game animals. Although no system of estimating killing power is perfect, Hornady's system includes such factors as bullet weight, sectional density, ballistic coefficient and impact velocity at 100 yards to derive HITS ratings to estimate and compare the killing power of rifle cartridges and loads at that distance.

Keep in mind that a cartridge suitable for a certain class of game at 100 yards may not be suitable at a longer distance. Keep all shots within the sure kill range and stalk closer when necessary, rather than attempting a long range shot.

Naturally, these HITS ratings are based on the use of modern, controlled expansion bullets suitable for the game in question. Varmint bullets, match bullets and military type full metal jacketed bullets are not big game hunting bullets and should never be used as such.

In addition to the extensive list of HITS ratings for hunting cartridges on the Tables, Charts and Lists index page, Hornady has a free HITS calculator on their web site that you can use to find the HITS rating of any load you wish.

I hope the simple guidelines that follow are useful to hunters. I wish that all game departments would adopt similar rules, instead of relying on caliber alone to establish the legality of big game hunting cartridges.

• Requirements for hunting all Class 2 game: Minimum caliber, 6mm (.243"); HITS rating 500-900
• Requirements for hunting all Class 3 game: Minimum caliber, 6.5mm (.264"); HITS rating 901-1500
• Requirements for hunting thick-skimmed Class 4 game: Minimum caliber, .33 (.338"); HITS rating over 1500

Let's look at a few common rifle cartridges to see how they score in terms of their 100 yard HITS rating. For Class 2 game, two popular deer cartridges and loads are the .243 Winchester shooting a 95 grain bullet at a muzzle velocity (MV) of 2950 fps and the .30-30 Winchester using a 150 grain bullet at 2390 fps. The HITS ratings for those two cartridges are 587 and 664 respectively, indicating they are adequate deer and antelope cartridges, which is confirmed by long experience in the field.

Compare those numbers to the 283 HITS rating of the .223 Remington shooting a 60 grain bullet at a MV of 3115 fps, or the .220 Swift shooting a 60 grain bullet at a MV of 3600 fps for a HITS rating of 328. You can see why even the most potent sub-.24 caliber cartridges should never be used to hunt big game.

Moving to Class 3 game, the extremely popular .30-06 with a 180 grain bullet at a MV of 2700 fps scores 1215 HITS and the hot Hornady .45-70 factory load using the 325 grain FTX bullet at 2050 fps scores a similar 1242 HITS. These numbers are well above the 901 HITS lower limit for this class of game and both of these are proven elk and general Class 3 game calibers. Conversely, the .25-06/117 grain bullet at 2990 fps scores only 814 HITS indicating that, although it is an excellent deer cartridge, it would be a poor choice for hunting Class 3 game.

For hunting thick-skinned Class 4 game, the 9.3x62mm is about the minimum recommended cartridge. Shooting a 286 grain bullet at 2360 fps, it scores 1863 HITS, comfortably above the required 100 yard HITS rating of 1501. The elephant busting .458 Winchester Magnum, launching a 500 grain bullet at a MV of 2140 fps, has a prodigious HITS rating of 3205!

The bottom line is these caliber and HITS ratings conform well to what we have learned in the field after over 120 years of hunting big game with smokeless powder rifle cartridges. They should serve as a simple and reasonable guide to selecting calibers and loads for big game hunting.