I mistyped the "Interbond SST," meant to say Interlock SST, which still wasn't right for what you're using...
I did make the assumptive leap that your shooting the Interlock SST's, not the "old school" Interlock SP - My bad!
Even with the IL-SP, it's a .406 BC, vs. the 100AB's .323. Less drastic of advantage, but still a more aero bullet, with a lot more punch on the business end.
But the Interlock SP is definitely NOT designed to expand at 6.8spc velocities. It's a .270win bullet, not a 6.8spc bullet.
The low BC's of the lighter weight "mag friendly" 6.8spc bullets are really what frustrate me about the cartridge. But it's nice to be able to get fat heavy bullets into mag length.