>.> shotguns have too many flaws to be effective, They are close range exclusive. A sniper rifle can shoot a close range target, a shotgun cant shoot a long range target. Shotguns have very little ammo. at close range you need to have nerves of steel to actually hit a moving target so that all the lead ends up shredding them to pieces. shotguns need you to actually specialize on them to be effective while anyone can get a rifle and start spraying.
When it comes to war, If it kills the enemy it doesn't matter. weather is by snipeing, shotguns, pistols, knives, mines, artillery, or F22 If the enemy Dies. It doesnt matter what you use. Also Better A living Coward than a dead hero.