Recntly i picked up a very nice 12g. Browning BSS in excellent shape. I normally shoot an sp10 or a super black eagle for water foul but would like to shoot a few ducks with this rascal before the season ends. The barrels are fixed modified and full. Can i shoot hevi shot out of it? How about bismuth? It is stamped steel special on the side but i dont dare try it. Thanks!!!

Do a google search for each of those as they have several web-sites that discuss what chokes etc are suitable for their shot.

Though this is not a definitive answer, I've generally heard that its best to stay with chokes no tighter than modified with either steel or hevi-shot.

With a "hell for stout" gun like the BSS with fixed chokes I don't think you'll really have any problems, but most say both types of shot pattern tight anyways, so you're better off with improved and mod.

Though that's just what I've heard.

FWIW. I called Browning and asked that question a few months ago. The response was, " Do not shoot steel or heavi shot in a fixed choke bbl". I knoww many people do but Bismuth is a better choice and it works well. Steel does not compress like lead and you may ruin a fine gun,

I would shoot bismuth- then you don't have to worry about anything.
If you insist on shooting Hevi shot or steel have the full choke opened up to .020 less than the bore diameter, this will give you a good pattern.

Ask Browning . That 'steel special' may refer to the type of steel the barrel is made from rather than the barrel being OK for steel shot !