Guy,
That recovered 165 .30 is typical of the expanded shape of the "super-heavy" jacketed Ballistics Tips. Their jackets are much thicker along the shank than most Ballistic Tips, surrounding only a relatively thin column of lead--the reason they retain more of the shank when expanded. The standard hunting BT's tend to open wider and "shorter."
Even when the super-heavy jacket BT's lose their cores, they normally retain around 60% of their weight, because there isn't much core to lose in the first place. Which is why they keep on penetrating even without any lead, unlike standard cup-and-coreds that lose their weight.
Have mentioned this before, but probably the deepest penetration I've seen with a super-heavy jacket BT was on a bull gemsbok, about the size of a typical mature cow elk. The bullet was the original super-heavy jacket BT, the 200-grain .338, and the bull stood quartering toward me at around 150-175 yards. The bullet clipped both the near shoulder and the bottom of the spine, ending up under the skin of the rump on the opposite side, retaining 59.4% of its original weight, despite losing the core.
