Aussiesteve. Good on you for going with what you wanted. Putting one of those 577 slugs in the right place should put them on the ground pretty quick. I had a Ruger #1 in 458 tropical rechambered for 450 3 1/4 express and I was told the recoil will be to much. It was quite managable. I was talked in to selling much to my discust. I have just bought a 450-400 Ruger #1. Haven't shot it yet, but certainly looking forward to it. Good luck with your hunt, and I agree that you do not have to shoot record heads or be a trophy hunter to enjoy your hunting. Let us know how you go.