@trekstor,
There are tradeoffs to be made. You need to decide the weightings of these factors for *your* project, for *your* application, in order to figure out which route is best. All that we can do here is help get you good info, for you to make those choices.
For a reasonable price, you can get an accurate semiauto. For the same price, you can get a more-accurate boltgun. For a higher price, you can increase the accuracy of either. At some price-point, you get into seriously diminishing returns.
For a given amount of money, rifle-building effort, and ammo-making effort, you will be able to achieve more accuracy from a bolt gun than from a semi. How much accuracy are you willing to give up, in exchange for how much of a quicker follow-up shot? Note that there is not a right or wrong answer here - this is up to you to decide.
There are other ways to get faster followup shots and better accuracy - with experience, your speed with a bolt gun will improve (*without* sacrificing accuracy), and so will your speed (*without* sacrificing accuracy) with a semi. With more testing and experience (and possibly handloading too), your bolt gun will shoot more accurately (up to a point) and your semiauto will shoot more accurately (up to a point).
There aren't a lot of bolt guns that will shoot half-MOA at 600m. There are even fewer that will shoot half-MOA at 1000m. Note, I did not say *none*, because I have seen such rifles fired, and it is a wondrous thing to watch when you see it done. But I will say that an honest half-MOA rifle is a heckuva lot less commonplace that many think.
Semis that shoot an honest half-MOA @ 100 are real (but, not as common as dirt!). It is harder to get an honest half-MOA at 600 semiauto, but certainly not impossible; it's a pretty top-end piece of kit though, and it needs pretty good stuff going into it (components, ammo), has to be built by a pretty good smith, and unless it's shot by a pretty good shooter it won't be very distinguishable from what an honest-1-MOA rifle will do.
