This is S & Ws new cartridge for the 500 frame revolver.  Ammo is by COR BON. Think of it as a 454 Casull magnumized.  The first factory ammo will use a 200 grain Barnes X bullet at 2300 and some change FPS from the 10" barreled revolver.  The same ammo does 2650 FPS from a 14"  SSK Encore.  Recoil is very mild for such a powerful cartridge. 454 and 45 Colt ammo can be used in the same chamber.

I got over 2100 FPS with a 300 grain jacketed bullet first try in the Encore.   I think there is another 1--200 FPS there with the 300 grain bullet.  Barrels are now available from SSK.