Does the bottom bullet have a hollow point? They appear to be jacketed. What is the core made out of? It looks really light colored.
If it is a hollow point, the hollow appears to be very wide, ala Speer Gold Dots which were derived from the 'flying ashtray', a semi wadcutter with a very wide opening.
This is all conjecture. Can you take some pictures at a different angle, lighting? Except for the bottom looking hollow the two bullets look almost the same.