Re: tikka ?
IMO, the Tikka T3 series is the best factory rifle out there. All of the one's I have shot and done load work up for were tack drivers.
If you can drive the rifle well, the 270 Win is more than capable for long range shooting. I have taken it to 1K out of a factory Howa, and it did ok. From 700 and in, it did great, but opened up some when I got beyond 800. This was with the 135 SMK. If you can seat the bullet close to the lands, the Berger VLD's would be awesome in it. Otherwise, I'd look at the 135 SMK or the Hornady 140 or 150 grain SST. The 140 SST would probably be a better choice, since the 150 SST has only a slight gain in BC, and you can push the 140 faster.