I really would not worry that much about the number of shells it can hold, because the gun will probably come with a plug, if not you can pick one up really cheap. I am also assumeing you are looking at the Super X3 all purpose field, so it will not hold 12 shells anyhow.

2 years ago I bought a Browning Silver Hunter, I love the gun and wish now I would have bought the camo coated version so I could use it to hunt duck, geese, and turkey also. You might check it out, a guy I work with just bought one on Gunbroker for less that $1000