Depends on when it was made.
No way to answer without knowing how old the shotgun is, what the 00 buck is made of and the choke of the piece.
You would use a full,or extra full choke if using 00buck for hunting purposes.If for self protection thats up to you.
You have a mechanical issue that needs to be addressed by a gunsmith
no
You might find them in the Blue Book of Gun Values.
#4 buck shot
You MUST call Browning to get a correct answer.
You risk damaging the barrels if you do.
Yes, in both the Superposed and the Citori. They can range in value just moderatly expensive to scarry.
No, due to the damage steel does to the barrels. Not recommended by Browning
Not recommended; will cause a bulge.