If a soldier ever gets into a firefight that lasts longer than five seconds, he’ll curse the day he decided to carry a shotgun into combat.
In WWI, shotguns were known as "trench guns," and the Germans summarily shot any AEF troops captured with one. Though it was only a movie, a good point was made my "Hicks" in "Aliens."
"I like to keep this handy...for close encounters."
A shotgun is a terrific tool for close in fighting, but, as you say, in a real, extended firefight, a shotgun isn't the greatest tool.
Mark