He wanted to start with locating the most hard to find or what one might call the holy-grail in pre-war bolt guns. he asked what rifle that would be.
I think that this might be different for each person, what say you, what do you consider the top rifle.
We had a similar thread a while back about a "Holy Grail" rifle. Opinions to a specific rifle will certainly differ.
At minimum, I think a "Holy Grail" candidate has to be a gun from a renown maker of the era, and a provenance to a renown owner. Engraving by a renown artist of the era, and a using gun as opposed to a commemorative would be a plus.
Most specific guns at the top of that pyramid are likely unobtainable now. But there are still examples a couple notches down with that same criteria.
My personal choice for a specific gun would likely be Jack O'Connor's .270 Mauser built by Alvin Linden. O'Connor shot more game with that rifle than any other he owned.
Grancel Fitz's Griffin & Howe custom Remington Model 30 would be another. Fitz killed all 25 (at the time) legal North American species of big game with that 30-06.