With the enlightenment from the commentary above a further potential advantage of Double rifles with their parallel bullet paths comes to mind.

Doubles are a natural for close hunting with pigs/cougar et al, but Scoped Doubles could also have a distinct advantage for a followup shot at distance on whitetail or other animals(200-300 yds out off shooting sticks).

Why?

The hunter with a bolt will loose the sight picture racking the bolt while the Double man keeps his grip and alignment and goes to the second barrel.Two fast aimed shots!!

That's NEAT!!

Maybe I need a small caliber Double afterall!!!