It is often reported that the 120gr. Bal Tips are simply shortened 150gr. Bal tips.
My little experiment in bullet sectioning proved this to be highly plausable.
http://www.outdoorsmenforum.ca/showthread.php?t=51520
Reports from larger and more broad based internet forums suggest that even when fired out of 7mm Rem mag, and the like, on game performance of 120gr. Bal Tips is quite good, and beyond what should be perceived.
Good luck.