I shoot the Hornady HPBT 75gr at short range and Sierra MK 80gr at 600 using Varget. The 69gr bullets you use are very good and actually shoot smaller groups in my gun than do my 75's but not enough to make up for the advantage in bucking wind at 300yds the heavier bullet gives me.
The bullets Parashooter mentions are also highly thought of.
Since the 600 yd stage is all slowfire, you can seat the heavier bullet out for a longer COL, just stay out of the rifling.
HTH

Doug
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