Rim-fire Cartridge: This is the simplest and (normally) least expensive type of ammunition available. Usually, the outer rim of the face of the cartridge is struck by the firing mechanism to ignite the enclosed propellant. This type is known as very reliable in small calibers and extremely popular world-wide. It is often used for plinking, varmint/pest control and small game hunting. Commonly available in .22lr caliber, a specific bullet-weight range must be used for satisfactory performance in semi-auto rifles and pistols. Oftentimes, ultra light/hollow-point bullets will not cycle the action in auto-loaders.
Center-fire Cartridge: This is slightly more complex than the rim-fire cartridge. Usually, the center of the face of the cartridge (the primer) is struck by the firing mechanism to cause a short chain-reaction to ignite the enclosed propellant. Center-fire ammunition is very common in small and especially larger calibers, notably in 9mm Luger at 115, 124 and 147 grain weights.