30 cal Tikkas are all 1:11 twist so 180 grainers are close to the limit for stability for longer range style bullets. I believe the 7mm’s are 1:9.5 which limits you to around 165 for best stability. Within those limits, both calibers have excellent options but factory Tikkas wont send the really efficient long range bullets acurately (probably). The good news is You will probably like to shoot your Tikka so much that you will eventually shoot the barrel out so you can rebarrel it with any twist you like!