I owned a .458 Lott in a Ruger #1 Tropical - sold it about six months ago. Now, I can't compare it to a 416 Rigby because I've never owned one, but I can tell you that I took the .458 on a bison hunt in Wyoming - and it knocked down that 1,500 lb beast without any problem! I used Hornaday solids, but I noticed that Federal has started making them too - and I love Federal bullets. The .458 Lott will get the job done!