I pulled the receiver off another '98. That receiver doesn't start either.
Got my verniers out & measured the barrel thread OD & the OD of the step before the threads.

New barrel measures: OD of Thread-.980", OD of step-.938"
Old barrel: OD of thread-.975", OD of step-.933"
So the Diameter is .005" larger than the old barrel. Goes along with the muzzle OD being larger too.
A friend of mine got a Carbine barrel & dropped a 220gr. rd in the chamber, went in to the rim. So not sure what to expect with the chamber untill it's mounted.