Hoppdoc.

I belive as the actual ammount of metal i.e. OD to Bore of the barrels is pretty much the same regardless of caliber an adjustment of the barrel lengths should take care of the balance, Say 28" in 9.3 and 24" in .500 . I would agree however that the rifle would be too heavy for caliber in the 9.3 chambering.
However some comprimises would have to be made for most switch barrel arrangments in any event even on a BA say 7mm mag and 458.

My thinking was that with a medium caliber double on PG the shots would be of a more deliberate nature if one were planning to shoot at over 100yds off sticks, so the extra weight would not be a handicap. If it were less than 100 I would be happy to shoot it with the .500 anyway.

I think that this is the problem with switch barrels in a nutshell. They would not be my preference.

I would prefer to carry a 400 class rifle with a claw mount scope and learn to shoot it at longer ranges with a scope, knowing that it is OK up to Ele.

IMHO most will never hunt Elephant and it calls for a special class of rifle not a one gun battery. If whilst hunting Ele some magnificent specimin of PG presents itself then take a lighter rifle off the truck or from the bearer.

Regards