I've been next to someone (about 15 years ago) that shot both barrels of a side-by-side right about that size. Both barrels fired, it spun, flips outta his hand, and landed in the mud behind him. Pretty kool to watch though!!!
Also, you will feel it in your wrists and palms. If you're getting up there in years it's not something you'd want to try. If you're young enough you just have to realize it will be less than pleasant. Buck it up. And, yes, I DO know first hand.
I've got an 18" Savage 311 and believe me, even firing it from the shoulder with 3" slugs or buckshot is not something you'd want to do too often. Once or twice, just so you can say you did, is enough. (YMMV, I'm a skinny 145 pounds @ 5'11")