I hunt at Fort Knox (as often as I can get drawn) and use a shotgun that I set up for that purpose.

I started with a Remington 1100 with a 28" Remchoked barrel (still use for Turkey hunting)...bought a 20" fully rifled barrel with rifle sights from Remington via Cabelas ($220)...had the receiver drilled and tapped and added a full length weaver mount...

I have two scopes set in quick release rings for that shotgun...a 3-9x40 for deer hunting with the rifled barrel (the rifle sights give me a backup system in case the scope fails during a hunt) and a 1-4x32 circle plex with the 28" vent-ribbed barrel for turkey hunting...

Modern sabot loads like the Hornady SSTs make a 20 gauge as effective as a 12 gauge for deer hunting...a 12 gauge gives you better flexability for turkey, waterfowl, etc.