Fairly simple: have the piston sized and adapted to the base, and die sized to fit and threaded into hand loader!
You do know he's making percussion caps from soda or beer can strips, right (but with far
less effort and stress - as well as far
quicker - than normal by hand)? Only thing left then is filling them (this
would probably help for that).
Only thing I'm curious about is whether or not (by using the mechanical leverage of the press,) is whether or not it would be possible to substitute a sheet of thin brass
sheet instead of aluminum.