Dont the smaller TSX bullets expand down to about 1800 fps or so? I would give Barnes a call and see what they say, no doubt the .510" bullets will be made tougher than the standard run of the mill calibers. I kinda agree though if the bullet is going to punch a neat 1/2" hole you wont need a bigger one to get the job done on an Elk! I'm pretty sure it will be enough gun fo the job at hand.