RE: turkey shoot guns
Mauser...I go to one for $$$ and attend weekly. Some shoots approach $500 for the winner of a single shoot. There are a lot of things you can do. Only rules we have are 36" barrel or less and .670 choke min. Most of us even shoot scopes. (It's 105' off-hand shooting) The normal beads on a shotgun cover up the paper at that distance.
I shoot a Rem 1100 that I bought a 36" grooved hastings barrel for. (Already back-bored) and I put a .670 choke in it. I also topped the gun with a 4X single dot Unertl Hawk scope.
It wins as many shoots as any other I've seen...and I've been around a few.
The smaller the choke doesn't necessarily mean a smaller pattern. A buddy I shoot with shoots a .680 choke that blows his .670 out of the water. It's dependant on the gun.
Many will say it's luck...and there is some luck involved. BUT, the same guys seem to do 90% of the winning in our league.