RE: turkey gun
Near any gun will work if you have the proper choke/shell combo.
I use a 20 gauge and will never go back to anything larger. Every gun will shot different so testing different loads with chokes will refrom a gun into a turkey gun. Choke Quality is one concern if you want to cut down some work, most chokes with long tappers will find a shell that will place the proper pattern. Cheap chokes do not offer long tappers and will make it hard to compete with a quality choke.
Don't fall trap to the 3 1/2 mags for a farther shooting gun, they only deliver a dencer pattern....