As far as fitting the round in an Arisaka action, you are mostly correct. It will not fit a stock arisaka action. But,it only needs about 1/4" of milling lengthwise to fit a round through the bottom, checked with some borrowed ammo. The fun part will be deciding whether to shorten the ejector, or move the whole assembly backwards. It doesn't need to go far, but it does need to move.
I will also need to open the bolt face, but I don't think that will be a problem.
As to the strength of the action, Ackley's notes were what actually inspired this. I had originally bought the reamer to build another mosin, but saw the tests on the Arisakas and decided to pick up a T99 action for the project instead.