I have owned a Tikka 512 for more than 10 years now. I have 3 sets of barrels: double rifle 9,3X74R, combo 12ga+7X57R and shotgun 12ga.
I see no reason why you shouldn't buy the gun. It's a bit "rough" in the finish- maybee a bit heavy, but it's a good workhorse- and I haven't had any problems with mine so far (and it's been used a lot)