I've read the firelapping tech notes for muzzleloaders and it specifies using a hollow based "mini" with a specific hardnes (BHN) of 11-12. Is this bullet available from Beartooth or does anyone know a source?

Beartooth has them. It's easy to miss, but read the first sentence of the paragraph that starts under the picture of the Goex can. Call Marshall at 1-888-423-2786.

Bye
Jack