Heavier gun = more robust - Maybe. But try not looking at the powder charge and looking at the Max bullet weight. I suspect you will find a common thread in all of the bore rifles and express rifles, but you will need to look at a good number of each since many were built to what the fellow who ordered it wanted and some were built for indian game, game on the home range and game ?.

Just as a for instance, I would have ordered a 9 1/2lb 450 NE rifle in the heyday knowing what I know now about elephant hunting, if I'd been alive back then.

JPK