I didn't believe #9 shot for turkey for a long time... until I tried it!
I'd like to try TSS out of my 56 cal smooth bore T/C, but figure the hardness of the shot wouldn't be too good for the barrel.
No way to load it in a shot cup? Isn't 28 Gauge .55 caliber? Some buffered #9 in a 28 gauge wad over some BP wouldn't work? Sorry, I don't use BP shotguns so maybe it's not plausible.