Haven't shot that far (yet), but mine seems to really like 140 Accubonds and 142gr Matrix VLD's with RL25. Haven't shot it for awhile, but if memory serves the Accubonds are running around 2970 and the Matrix about 2950 in a 26" barrel.
Fed215M primers, worked up to 54gr with the Accubonds and 52.5 with the Matrix. Probably could have gone a little more with the Matrix, but found good accuracy at 52.5 (one ragged hole @100) so haven't tried yet.