My .06 really likes the 200 gr Sierra Match Kings. I would also suggest that if you can switch to the H-4350. It seems to be less temperature sensitive than the IMR.
While that may be true, it is not all of it when it comes to many of the matches in the area. Consistent trigger pull, cheek weld, breathing, positional shooting and racing against the clock are all needed skills that can be practiced at any distance.