From time to time a rifle needs to be rezero'd anyway, a .1 here or there, Not a big deal to do. Wish life was perfect but only the case on the internet. Not saying a zero can't be true for a long time, depends....
Hadn't shot my Anschutz since spring, "local match director keeps cancelling matches or changing dates". checked the zero for tomorrows out of town match, it was off .3 mil, I don't know why??, it is what it is.
The zero is your reference point, off at zero, off at distance.
If your dope is good you can back in the dope from a distance, often being on or close to it at the reference point/ zero. Not the best way to do it but when I've changed out scopes and didn't have to time to zero the rifle I made do and it worked fine, this is just goofing around with friends, not at a match.
But then .1 off usually still provides a hit on medium sized steel. Adjust as needed.
If you are switching barrels just go with the flow, you may or may not need to reset your zero, life is hard, lol.
OP, I think you are on the right track by buying a quality action to begin with!
Had many cartridges throughout the years. This time I went with 6mmBR on the go-to rifle and have not regretted that decision. Shooting at 1013Y last week with some new friends that I hadn't shot with before. They were amazed how easy it was for me to hit steel in 10-15 mph winds compared to their 30-06 using 210's and a 338L with 250's. Shoot fast before the condition changes, lol.