I agree the Snider is an interesting rifle.  In mine I am shooting a 630 grain flat base round nose paper patch bullet and it shoots quite well, better than I expected even.
The Britts have a bit of an advantage as they can import from Spain for Mag-Tech brass as well as from down under for Bertram brass . Right now neither are being imported to the USA. There is no domestic source that I am aware of.  Mayhaps if we are loud enough Starline will hear us.