Re: 168 vs 175 VLD
JesseBB,
No, they're absolutely the same at all ranges, until the ballistic shortcomings of the 168 becomes apparent. Then the 175 will start to give better groups. No inherent difference in the accuracy of these bullets whatsoever at shorter ranges, which shouldn't really come as a suprise; same core alloy, exactly the same jacket (different trim length, all other specs are the same) and a nearly identical profile. They're also shot to exactly the same QC standards for acceptance, same range, same group size, etc..
Your individual rifle may show a preference for one or the other, but that's a different issue. No difference in the bullets themselves, though.