If we’re not rolling our own already, start (will be difficult). Look at getting a muzzle loader also. Not a rapid fire tool, but they work, and components are still to be found (as of last week anyway)at local Dick’s.
YMMV
KYPD
Dick’s is off limits since I took my four year old in there and Aerosmith’s “Big Ten Inch” was playing over the PA.
Besides, for the price of a muzzle loader and all the fixin’s, you could just set aside more ammo, and get more shots out of it too boot!