Basically a .375 Ruger necked up to .416
http://www.hornady.com/story.php?s=790
http://www.thefirearmblog.com/blog/2008/11/16/new-416-ruger/
Unlike the .375, the .416 in my view will have far less competition, and perhaps will become a success as well as a great cartridge.
Much easier to talk a guy into a .416 Ruger over a .416 Rem or .416 Rigby than talking a guy into a .375 Ruger instead of a .375H&H.