The top gun here, is a 6 bore(.92")of the early 1800's era- maybe 1820-ish. Very nicely proportioned.
The other two are 24 bore (.58's) rifles, I think.
The size difference is quite noticeable. The bottom gun in the picture could be of smaller bore, yet, 28 bore, maybe (.54).

4-bore Blunderbuss. Of course, the belling of the muzzle for loading in a carriage or on horse-back is evident in the bottom photo.