Froggie, back in the dinosaur days when only fishermen had nets and spiders had webs, I picked up this cute little rook rifle in 300 Rook. Closest brass was 32 Long Colt so an operation was performed. It was actually possible to find an occasional box of ammo back then and I got one. In the modern age Buffalo Arms came along with a mold for a little 300 bullet so now I needed more brass. Took me several large gunshows to find a collector with a box of matching factory ammo. Was not inexpensive but necessary. It may take you a while now but at least you have many more possibilities for searching. Good luck.