The term "closed season caliber" refers to calibers and their cartridge ammunition that are used during the closed season for big game and small game. During this period, mainly predatory game is hunted (or, in general, game that may be hunted during the entire hunting year).

Small calibers that are gentle on the belly are recommended for hunting predatory game. The most common are.

• .22 lfB
• .22 WMR (Winchester Magnum; also abbreviated .22 WinMag)
• .22 Hornet

Since the .222 Remington is already approved for deer hunting, it is not counted among the closed season calibers.