My personal preference is a Winchester SX3 deer gun. I'm sub MOA at 100 yards with 2 3/4 accutips.
We have a few 20 ga users in our camp - IMO, if the shot isn't in the boiler room the deer isn't dying anytime soon. This is just my opinion based on my experience. There is NO room for error with these 20 ga sabots in my opinion. One example my sister shot a doe twice at 100 yards with 2 3/4 inch accurtip. First shot was off the mark by 2 inchs and hit the shoulder. Second shot through the boiler room. Double lung. Deer died about 30 yards away. When skinning we discovered the shoulder shot didn't even go through the shoulder blade. If shot 2 didn't connect than it was a wounded deer - not fatal.