That's "superimposed" and does not add to or subtract from the value. It simple means the two barrels of a double-barrel shotgun are "over/under" instead of "side-by-side."
FN is the abbreviation for Fabrique Nationale Arms Co. of Herstal, Belgium. They made most of the A-5 shotguns and Superposed shotguns for Browning USA.
It is the model name of the first Over/under shotgun that Browning made. "Superposed" in the dictionary means "one on top or over another".
This is a double barrel, over/under shotgun.
Unsure of your meaning of "break away shotgun". If you mean breakdown shotguns like double barrels they continue to make several different models.
Your adding more stuff to make it worth whatever it is or to just make it valuable
The Dictionary says: "to place above or upon something else, or one upon another." As in the case of the Browning shotgun, the Superposed model ws the first sucessful Over/Under shotgun ever made. Browning used the dictionary description to name the model "Superposed" because one barrel is apon another.
Things in your home that are valuable to you.
Most Valuable Player Most Valuable Professional
If by "this service" you mean FAQ Farm, then yes, it is very valuable.
It does not mean valuable.
Shotguns don't use bullets. Do you mean without a case or non lethal projectiles? If so, yes they have caseless ammunition.
BB = Ball Bearing. It a form of Shot, used by shotguns.