Among ammunition suppliers, .22 caliber rounds rank among the smallest commonly available, and are adequate for hunting small game, such as varmints, and sometimes larger targets at long range. Rounds including the .243 and .30-30 Winchester, the .300 Savage and .25 Remington are adequate for most deer, particularly at short range.
Experts consider .33 caliber as beginning the category of ammunition designated medium bore. This is generally used for hunting large cats, such as mountain lions, bear and hoofed animals categorized CXP3 (controlled expansion performance level three), which are heavy-framed, thick-skinned species including elk, moose and zebra. Calibers ranging from .375 to .416 are commonly good for CXP4 species, the next biggest level to CXP3, which includes extremely large game such as rhino, elephant, hippo and cape buffalo.
For specialized bear hunting, the .300 and .338 Winchester magazine rounds are preferred for grizzly and brown varieties, whereas .444 Marlin and .45-70 government issue are often used for black bears. In addition to caliber size, it is equally important to discern bullet style. For instance, lever-action rifles with tubular magazines require round, flat-nosed bullets to avoid chain misfire in the magazine. Smaller targets, such as varmint, demand bullets with soft cores and thin jackets, whereas many larger game require thicker, tapered jackets to ensure deep penetration and the weight retention of the round.