The kind of ammo varies from smaller sized caliber weapons including the hand held weapons within the type of revolvers, pistols and a number of rifles to moderate caliber automatic and partial automated weapons and shotguns or perhaps the bigger caliber artillery weapons and special arms.
Munitions however is a group name for bullets as well as in a broad expression it handles all variety of supplies used in combat and involves bombs, warheads, missiles, etc. Ammo also may include those according to the help roles including the pyrotechnic or incendiary different kinds of munitions.
When talking about firearm calibers generally the best way of knowing it is something as the following: The larger the grade the greater the stopping energy but the more difficult this is to operate. So a higher grade firearm is needed for much larger animals but you will also experience a lot more of a knock with the recoil of a better caliber.
Remember also that the hole made in the target will probably be bigger for bigger calibers and that is why the proper kind of weapon will have to be selected depending on the game you’re heading searching for.