I really like the 300gr XTP (.429) bullet. I have shot it extensively in my 50 cal muzzleloader and few 44mag rifles. Does an impressive job on whitetails.
I recently had the same question as you regarding the 300XTP and large hogs. In the end I decided to go with a 300gr Swift A-Frame bullet and was glade that I did. The Swift may have been sturdier than necessary but it put a 300+ lb hog down quickly, with only one shot.
I originally worked up my load for the 300gr bullet by using the Hornady XTP and was able to use the same load with the Swift bullet. They also had the same point of impact out to 85 yards, which was as far as I fired them with the open sighted revolver.
VH