This is a pretty cool thread

. I might make a rifle version of this thread down the road as Assault Rifles are my go to but if I had too choose a few shotguns I'd hope to see. I'd definitely second a few others have said. But here are some.
Since it has the whole rural red neck vibe and it is in Montana, I don't think it'd feel accurate without the old fashioned double barrel sawed off. It's a staple in America and especially rural areas. It's 2 shot classic appeal might make it limited compared to a shotgun with a nice clip semi auto but it sure is powerful at close quarters.
I have to second the USAS-12. It's a complete monster and customizations on it would probably be the most lavish and upgradable. Spraying this at bears or the such would be pretty montana if I do say so myself lol.
Of course with these you know their are so damn many of them everywhere especially in the rural areas. It's a old school trench gun. One of the more popular shotguns and iconic till this day.
SPAS-12 . This shotgun is seriously overpowered in most games Ive used it. A nice compliment to the USAS-12.