As was alluded to by several others, the Kent pellete are soft enough to use in traditional full choked barrels. They are however not available here in bulk and should you chose to work up a low pressure load for them from dissasembled shells, you should use a fully enclosed shot column...be it paper wrapped or full plastic shot cup, as it is abrasive.
Have not had any problems with bulk Bismuth pellets shattering, and do not hesitate to use fiber wad loads without a wrap or cup in full choked damascus(or otherwise) guns. Will deposit some material on the barrel if unprotected, but comes out fine, just like lead.
Best,
Mark
