Not with that rifle or that bullet specifically. A friend of mine has developed some loads using heavier bullets with H1000 I believe. Don't quote me on that however.
The heaviest I've tried through my 1-10 Tikka has been the 90 gr Accubond. I used IMR 4831 which gave me good groups at around 2950 fps. Not a blistering fast load by any stretch, it's been my experience that the Tikka with the slow twist 1-10 barrel shoots the best at moderate to low velocity. Not a ringing endorsement for the .243 considering speed is a good thing with a 6mm bullet, but that's what I've found.
Even with 70-80 gr bullets my most accurate results have been in the 3060-3080 fps range.
I think Tikka missed the boat by putting solely a 1-10 barrel on the T3, it removes some of the heavier bullets from the equation. Perhaps the Finns considered the .243 to be a heavy varmint cartridge rather than a medium-large size game getter.
There's a good chance others here have had different results, my load testing was by no means exhaustive.
