I have tried 180 accubonds 180 Barnes ttsx and 180 sst with no groups better than .9 at 100. I have used rl19 imr 4831 and 4350 and h4831 and 4350 and imr 7828. Fed 210match wlmr and cci 250 primers. I have some rl22 I'm going to try with the 180 sst. I'm considering trying 185 Berger classic hunter or 190 Accubond lr any body tried these bullets in a tikka?
I think you are onto it here. I think the 165 is the sweet spot for a 1:11 twist. It will shoot the 180s but I think it will really tighten up with 165s. Have seen similar results with a Sako 300 WSM with 1:11 twist.
I had same problem with 180 grain ttsx. I think all copper bullets are too long for the twist in tikka. I dropped to barnes 168 ttsx and .5 moa at two hundred yards. I use win 760.
I got some 168 Berger classic hunter I loaded with imr4831 and a cci250 primer. Going to shoot them this morning.