As far as rifles go, my Remington 600 chambered in .350RM. It's ridiculous. I don't think it's necessarily the caliber, but the lack of weight.
When it comes to shotguns, hands down, my buddies H&R Topper 10 gauge Turkey Gun. It will lay a turkey down at well over 60 yards with pellets to spare. It will also dislocate your shoulder if you aren't paying attention when you squeeze one off.
I have a 660 in the same caliber. One of the first things i did was get rid of that factory kickpad that after all these years was rock hard. replaced it with a limbsaver, and it's nothing now.
