"...a cylinder bore. Anybody had experience with one of these? How about buckshot? Could I just use a cylinder bore and just dump in more shot to get a denser pattern?..."
I've really gotten a lot of enjoyment out of .54cal/.28ga and .62cal/.20ga GM Flint smoothbore barrels...doves, squirrels, crows, turkeys, and some clay targets.
I use the old rule of thumb "little powder, more lead, shoots far, kills dead" and its worked well for me. As an example, in my GM .28ga, I use 70grns Goex 3F and 100grns #5's...bagged 2 squirrels at 30 yards off the same beech tree one afternoon. (No modern shot cups with any of these)
So yes, cylinder bore guns are great, and to be honest an awful lot of small game is taken in the 18-25 yard range, pretty well covered by a cylinder bore.
A tiny skeet target crosses at 21 yards and 60grns 3F with 70grns hard #9's does fine.
And with a .62cal I had jug choked 'Full', a made a couple of head shots on toms out at 40 & 30yds respectively...so when the rifles start to get boring, a smoothbore opens up a whole 'nuther world to experiment with