Water quenched wheel weights come in around BHN 21, which is almost as hard as lino, and not as brittle, and heavier. In addition, if you oven treated them and water quenched after mixing ww with lino, BHN goes in excess of 33, which is a LOT harder, as base wheel weights run about BHN 13 after cooling normally.
I used to have a casting business, and I used to move a lot of the oven treated variety for use in ball mills, I got a LOT of complements on how hard these were... Lots of folks making their own fireworks and some making other things that needed grinding and that were not subsequently eaten really did like them. I imagine if one wanted to poke holes in something, that would be the ticket if it was not in contact with a barrel. I would NOT try using something that hard in a gun barrel contact situation on game, because though it would not obturate in the bore, it also would not expand in game either....