The .585 Nyati cartridge was originally a wild cat cartridge developed by Ross Seyfreid (Guns & Ammo write and
famous shooter) by modifying the 577 Nitro Case, and reducing the diameter of the rim, making the rim slightly rebated.
Now brass is being made for this caliber.
The 585 Nyati is one of the most or the most powerful "Shoulder-Rifle" cartridges in the world, with over 10,600 foot
pounds of energy. NYATI (N-Ya-Te) means "Cape Buffalo" in many African tribes.