Wow, some amazing info that will do me no good but loved reading it!
My take was 338 Lapua (designed exactly for the purpose of "to go long" accurately.)
And ditto on cost. Worried about a sheckle here or there for what you are putting into this?
Ok to fiddle, it human, its fun, but I am not into a twisted sort of rational, just admit its fiddling (or slicing the onion finer still)
At this point the rifle and pistol spectrum has been sliced and diced so finely there is nothing new under the sun.
Now perpetual motion, thee is a field you can really make in impact in!