If you own a 12-gauge shotgun then chances are that it is either a pump-action shotgun or a semi-automatic shotgun. Both types of shotguns can do significant damage to the target it hits. However, like all firearms, they are quite loud and could possibly scare away other potential living targets. As for those in a combat situation, shooting a shotgun could alert additional enemy forces of your whereabouts. For this reason, you would need a silencer attachment for your shotgun to prevent those loud sounds from being made.