Alex, if you only want the shot, buy Ecotungsten's "Niceshot". It's cheaper than your friend's bismuth and heavier, ok for old doubles, reloads the same as lead (no buffer needed), and you wouldn't need to dissassemble a zillion shells to get at it, or seperate the 3 different sizes (if you don't want 4s, 2s and BBs mixed together)!
Joe