I used the 300 grain XTP, loaded warm with 296 powder, out of a 7.5 inch Redhawk to take a Maine bull moose. One shot thru the shoulder at about 40 yards. The bullet performed well, expanding some, and recovered on the opposite side under the skin. Bull traveled about 40 yards after being hit.
Used the same load on a decent sized wild boar with similar results.
Nice thing about the 300 grain XTP is that even at lower velocities, you should get some expansion, as well as deep penetration.
Have also taken a couple whitetails with it, and while it certainly worked, I like the 240 grain XTP in that role, as they seem to expand a little quicker, offer plenty of penetration, and kick a little less in lighter weight revolvers. XTP's do have a slightly thicker jacket then many other 240 / 300 grain .44 bullets, and are at their best in the upper velocity range, where they hold together, expand well, and penetrate. I have taken a fair number of deer with the 240 XTP, and it is my favorite deer hunting bullet.
Larry