The only bullet that might tumble would be a short (light) full wadcutter bullet being shot at 50 yards or more.
I thought the heavier and longer the bullet, the faster the rifling twist has to be to stabilize it, so if anything, a short wadcutter would be overstabilized.
Some hollow base bullets will actually fly nose first even when shot from a smoothbore. For example, you can shoot .177 pellets from a smoothbore BB gun all day and every one will hit the target nose first, at nearly any range you shoot from. That's because the heavy nose and hollow tail makes them naturally stable even without spin.
Maybe it's the tippe top phenominom, these mushroom shaped tops are stable without any spin but when you spin them, they start spinning on their sides and then flip upside down and are stable that way as long as they are spinning. Maybe hollow base wadcutters do the same thing and need to be shot backwards to stay stable at long range, especially when high velocity gives them a very fast spin rate.