Most really big bore shooters don't actually hunt with them...but if your going to hunt Africa then weight of the rifle is very important...10.5 lbs. is about max in my opine and that get plenty heavy by the end of the day in hot rough country....

I would opt for a 9.5 lb. 450-400-3", a 10 lb. 500-416 or a 10.5 to 11 lb. 470 max.....

I have shot and owned a number of doubles, but for hunting I like my searcy .470 better than anything so far..It is superbly accurate at half inch one hole groups most of the time at 50 yds. from a rest and it will shoot hot loads and lighter loads to the same POI, solids and softs to the same POI, it will shoot monolithics and I can load it with a 500 gr. bullet of any kind and it will get me 2245 FPS or with a lighter load 2020 FPS at same POI..If it gets lost then I collect the money and have Butch make another, it cost about $9500. It is a hunting rifle pure and simple and it works.

If I wanted an investment then I would buy a high dollar English double rifle at about $50,000 give or take a little., thats better than the stock market..