Jay, notice it's what's referred to as a "smooth rifle"...stock is basically a rifle stock architecture and the barrel has a rear sight.
I hunt in thick woods and sight in everything for a 50yd zero...longest buck I've ever taken was only 70yds, and so far at these ranges my smooth rifles basically shoot about as good as a rifle...their norm, shooting from a seated hunting position leaning against a support post as if it was a tree (no bench) averages 2-2.5" at 50yds.
I've also found through load development that the faster I push a PRB out of a smoothbore, the more accurate it is...my conclusion being that they stay under a pretty good head of steam for more of the distance to the target, and they can't slow down enough for the knuckle-ball effect to creep in.
If you get a first smoothbore, and assuming you'll want to hunt a wide variety of game, my suggestion would be the .62cal(20ga)...gives a little more flexibility for larger shot loads of larger pellets than the slightly smaller .54cal(28ga).
My .62cal(20ga)...a true .620" bore:
110grns Goex 2F
.022" Oxyoke prelubed patch (labeled .020" but measure .022")
.600" ball
