Firearms legal for big or trophy game hunting must have a barrel bore diameter of at least .23 of an inch and chambered to fire a centerfire cartridge at least two inches long including a soft or expanding point bullet seated to a normal depth. Shotguns fit these categories as to bore diameter and cartridge length, but are legal only if a single projectile is used. The law stipulates that the cartridge must include a soft or expanding point bullet. A shotgun slug would qualify here but buckshot loads would not since shells loaded with buckshot involve the use of multiple projectiles. Except for a few deer and antelope areas, Wyoming does not have special muzzleloader seasons.
Many hunters use muzzleloaders, but they generally hunt during a regular firearm season.
Wyoming archery and firearm hunting seasons are already quite liberal in most areas and if additional seasons were created it would likely cut into the time allotted for other hunts. A. Wyoming law prohibits the possession of firearms while hunting during special archery seasons and while hunting in archery-only areas. However, if you are bow hunting during the regular firearm season, you can carry your handgun. An archery license is required only for people hunting big or trophy game species during the special archery seasons. It is not required for hunting small game, game birds, unprotected nongame or predatory animals.