Jeff,
The 1:12" twist should stabilize up to 168-gr conventional bullet in your '06. And while the 130-gr X-bullet will perform at 400 yds, wind drift is still an issue regardless of mfr's bullet. You might wish to also try the
150-gr Triple Shock X-bullet. That would drift less than the 130-gr bullet,
and what you'd give up in velocity would be compensated for in BC (3100+fps w/.374 BC vs. 3000+fps w/.428 BC).