Sometime back, I read an article about the lever gun headspace. It actually advertised an oversized bolt block.
This and a couple more things are on my bucket list. After I get a little bored with thenew rifle.
I have the softback book from the guy who writes about accurizing the modern rifle. He speaks to the crappy way some of the big name lever gun makers put on a barrel. In the book he writes about the DYI method of marking, turning off the barrel, valve grinning compound, going very lightly until one just barely gets an interference  fit. He states that Marlin was/is one of the biggest offenders using really cheap barrels for their guns. 
To the garage gunsmith here, it would seem rather easy/quick to true a barrel and true a receiver before installation. 
Mick stated that the torque that results is prevalent in a lot of the inexpensive lever and bolt guns. 
And, of course, the last thing is to install an air gauged XX Douglas barrel about 30" long. Octagon.