Hi Fuhrmann..

What "hunting-experience" are you looking for..nowadays? or historical?. There are a few who still bring these bore-rifles on modern safaris. They are posting on this forum too.Do a search, and you shall find..hahaha
You mention "old weak bore rifles"...well. They may be weak compared in construction compared to newmade doubles, but powerwise these weak borerifles can actually supercede most of the modern calibers...with exceptions ofcouse.
I see you are from Suisse...My mother lives near Biel