I still do not believe expansion of a bullet with an original diameter of .452" is essential in "putting an animal down well". Case in point, is one of the deer I shot with a 400 grain Speer Golddot from my .475 Linebaugh. Now, I measure penetration in feet with this round, not inches. By the looks of the opposite hindquarter, portions of the broken femur created the damage, not the bullet. The femur in the opposite hindquarter was broken after the bullet broke the upper bone of the onside front leg and traversed through the body cavity. Even with the bone shards, the exit hole was not overly large or messy.
Hard cast or heavy jacketed bullets are very much suitable for use on deer. I have shot many deer using the 260 grain FA bullet while getting ready to take it to Africa. These bullets are leaving the barrel of my 10" at nearly 1900 fps and like the .475, I measure penetration from this bullet in feet, regardless of the size of the animal I shot.
Stopping an animal requires the structure (bones) be broken or the central nervous system be overloaded and disrupted. If a bullet is not able to penetrate adequately, this will be much more difficult to acheive. The mag versions of the XTP in .452 are built for the FA revolvers. Because the velocities this round is capable of, the jackets need to be heavier. The 260 and 300 grain JSP made by or for FA is a tough bullet by design. One can very easily overdrive a bullet with this round and not only damage the revolver, but actually reduce some of the performance potential of the bullet being used.