There is a lot of information about shotguns, chokes, and loads, that has been discussed on PredatorMasters over many years. A search here can give you a lot of solid information from some very knowledgable shooters/hunters with real experience. I'm stating this because I wouldn't rely on just one person for information (that is not directed to anyone in particular, that includes me in the group). I'd draw information from as many reliable guys as I could. You will find that while there naturally are a few differences of opinon, there are also a great number of guys who seem to use the same basic set-up. That must be a recipe that works if so many good shooters/hunters use it.
Usually that is a variation of a turkey gun. A repeater in .12 gauge, mostly 3" or 3 1/2", semi-auto/pump, short barrel, drab/camo finish, sling equipped, accepts choke tubes. Some sort of high visibility sight is usually present, or, even a glass sight of some type is mounted. The choke is pretty tight, from around .685" - .660", and, the load is plated lead No. Four Buck, BB, or Dead Coyote.
Here is mine. A Benelli M1S90 semi-auto 3" .12 gauge camo turkey gun with 24" barrel and fiber optic sight. Sling equipped and with a Kick's GT .660" ported choke tube it patterns Federal Premium 3" .12 ga. No. Four Buck well enough to clip a coyote to 50 yards reliably. Been using that combo for the last 5 - 6 years. Before that was a Remington 870 .12 gauge turkey gun set-up very similar. Before that a Browning A5 with 26" barrel with full choke and loads of BB's did the trick, though not as well as the Benelli. Here's my Benelli...