Depending on the 98 bolt type installed, the ejector guide slot face/tip/end-to-barrel or extractor-to-barrel gap should be zero or minimal - ideally the guide slot end or extractor should almost (or even just barely) touch the barrel face. Closer is better. From here on I'll just call this the extractor-to-barrel gap. The case extractor groove is unsupported, but you should do things so as little of the case head as possible is unsupported...which is why we want the extractor-to-barrel gap to be zero or as close to zero as possible.
When rebarreling a 98, the way I do it is to first check the bolt locking lugs to receiver locking shoulders for area of contact. You might have to lightly lap the bolt locking lugs to the action locking shoulders with a lapping tool - lapping only enough to get at least 75% - 80% contact on each lug while being careful not to break through the hardened surface of the action locking shoulders with too much lapping. (Doing so results in locking lugs set back, and many times claims of "soft" actions). Then, depending, I might true up the face of the receiver and possibly the face of the inner "C" collar (again lightly!). Next, I short chamber and install the barrel so that the barrel breach face contacts the inner "C" collar .001" to .002" (max) before the barrel shoulder - this is how Mauser designed it and with reason (be aware there are some "experts" out there who spout this isn't necessary...however, it's actually a safety thing and I tend to think Peter Paul Mauser knew a bit more about his design than they). I check the extractor-to-barrel gap and, if good to go, set final torque/headspace. Nebulous and perhaps I missed a step or two, but that's the quick condensed version.
CB
