Sounds to me like an exercise in destruction of the person shouldering the weapon to me. Being a machinist and owning a short run production job shop, I can tell you with certainty that 'reaming' and 'boring' are 2 different things entirely.
You don't 'oversize' any bore with a reamer. A reamer only removes maybe a couple thousands at most, to achieve a final fit/chamber dimension.
Your understanding and the actual procedure are 2 entirely different things.
The 'proper' method would be to fit a quality barrel blank to the action and 'ream' that to dimension with the appropriate reamer, in my case, I use PT&G reamers.
I guess to avoid confrontation with those that hold 'assault' type rifles dear (I don't, never have, never will, though I do own a Barrett 50, which is arguably, the most assaulting of assault rifles ever produced for general consumption...if you can afford one), I'll refrain from using that word and stick to what I'm familiar with and that is fine tuning rifles for sub moa/mil accuracy at distance and building custom sticks.