What pistol are you using? Some 2400 loads and without looking, all H110 loads will disassemble a SAA. Maybe not on the first shot, but shortly thereafter. If it were a cast bullet, I'd say that 1,000 f/s is enough for a pass through on a broadside shot. Given the fact the XTP expands, the parachute you'd be pushing through the animal would require more velocity to make an outey. How much more? If I were loading a Black Hawk, I'd go with a minimum of 1,200 f/s or more but I don't have any data to support that. That's muzzle velocity though and I'd take a 50 yard shot with confidence.