I am installing a bull barrel on a Mosin ,I hand tightened the receiver then torqued it another eighth of a turn checked the headspace with a PTG headspace gauge ,go gauge, I cannot close the bolt should I get a chamber reamer and go from there? My other question is can the extractor cut be done on my drill press with a end mill bit or other tool?
Oh boy...where do I start?
Lemme guess...McGowan? I have three of their "prefits" in here now ( I don't know anywhere else you could obtain a bull barrel in .311, that would be threaded to fit the MN receiver).
You apparently didn't realize these require gunsmithing (McGowan states this)- either professional, or hobbyist with a lathe- to install.
You're in over your head, if you even need to ask these questions- no offense, this isn't a Savage project.
Assuming still you have a McGowan, it's fully chambered (at least, it's supposed to be. I had one that wasn't and needed to be reamed a few thou).
Headspaces off the rim. Even if the chamber needed to be deepened, that has nothing to do with the bolt not closing on the go gauge. There could be NO chamber cut (as Wyosmith alluded to), it's all off the breech.
Now the odd part...McGowans are supposed to be short-shouldered, meaning the shoulder gets set back on a lathe to headspace. Last couple I got, were very close to spec- not sure why. I'd rather have 20 thou to turn off than 2 or 3.
Anyway, if headspace is too tight the breech needs to be set back, and the chamber reamed back to depth.
I hesitate to even ask...but you
did remove the extractor from the bolthead, right?