Gentlemen, I have wanted a double rifle for a long time. Do I need one? No. I have more bolt and single boomers than I will ever need. My mind was poisoned at an early age from reading Africa hunting stories. Early on mention of a .577 got the wheels turning. Years later I started buying rifles as dollars allowed. Two of my favorites are my custom .416 Taylor and my Ruger .416 Rigby. Both are very accurate and managable. I still want a double. One of my hobbies is collecting actual on game performance data from big game hunts. In the process of watching hundreds of kills on video the cartridges that I always though would be stand-outs have not been the best performers. The .577 I thought I would have to have averages 4 shots per buff taken from a sample of 6 kills. The one cartridge I figured would been bringing up the rear (450/400} averages 3 shots from the videos from a much larger sample and from an even larger sample I have seen more buffalo on the ground from 3 shots or less from the .416 Rigby than any other rifle. Unfortunately the sample size of .577 kills and .600 kills are considerably smaller than the rest. Obviously there are less guns in these calibers around.The .470 which I also expected to be a run away is a 4 shot average as well. I am sure that there is enough experience here to add to what I have gathered. MY first trip to Africa is going to be with my .416 Taylor. It just works to good to leave it at home. Price will matter since there is no such thing as a cheap double. I have found a few good deals on 450/400s from time to time. Much cheaper than any .577 except for a few .577 BPEs running around. Also since from the data base the .416 Rigby did so well I would also expect the 500/.416 to do well. What do you fellers think? Experience in the field with the 450/400? reflex264