Thanks to all of you for nice responses!
I have handled but yet not shot the Chapuis. Very nice gun, but since it is so light weight maybe it requires a light scope to maintain its balance? The scope I have in mind is heavy at 18,5 Oz (525 gram).
Good idea to have the chance to fit extra barrels. Maybe a .375 with an extra barrel of 470 or 500 later if the double barrel bug hits me real hard. Do you think the gun will be as well balanced with the extra big-bore barrel attached, as a separate gun in the same calibre would be?