With todays new bullets sectional density is meaning less than it used to as well.Bullet construction means far more than sectional density.For example the 7mm- 140gr failsafe or barnes x will easily outpenetrate a 7mm- 175gr corelokt or power point(or most 175gr bullets for that matter) although the heavier bullet has a much higher sectional density.Sectional density is now only a concern if you are comparing bullets of conventional cup and core construction .Even the new bonded core bullets behave differently.