I have some of those Hammerhead rounds as well but never noticed any significant difference in recoil. There should by all reports however be a drastic difference at the other end!
There is no need to use anything bigger than the 300 grain rounds for deer, bear, moose or bigfoot here in the Maine woods. One of the best uses for those hammerhead rounds is for close in bear defense in areas like the Alaskan coast. I believe that they were the top choice of one of the US agencies for that very purpose.
No, unless you happen across a 2000 pound carnivorous whitetail with supplemental armor added you won't need those Hammerheads up here.<img src=icon_smile_big.gif border=0 align=middle>
“He who joyfully marches in rank and file has already earned my contempt. He has been given a large brain by mistake, since for him the spinal cord would suffice." -Albert Einstein