Have not used the 155's. I'd think they would be pretty explosive at shorter ranges.
If they are started at 16-18" barrel velocities, the 168 ELDMs are still pretty explosive (but not insanely so) at 100-150 yards. And they still fly well and kill okay at 600. I've used them a bunch in 16" 308s for exactly what you're talking about.
But anything tipped and thin jacketed in the 175gr-178gr weight range should also work well (ELDM/TMK). My inclination would be to err on the heavy side just to keep the speed down and let the fragmentation do the work.
