I recently saw one of those retro- history shows on cable TV. They were disproving that Billy the Kid killed a guy with a load
of dimes. I don't know if Billy actually did this, but I can tell you
that about anything that you load up in a "Black Powder" shot
shell is going to be blasted out. That is not the case with modern
smokeless powder. Without proper compression things like dimes
Will not have much velocity. If you have tried you hand at buck
or slugs you know what I mean. Me and grandson loaded one
with dimes and FFG, using old BP hammer gun we shot at a
Piece of 3/4 plywood. Most of dimes penetrated ply, except 3
that hit flat ways. Grandson was happy with test results until
he found out we used his Ice Cream money!