And don't forget that the locking surfaces of bolt and body are cut to a 1: 0.10" helix; they are NOT straight or at 90 degrees, like most modern sporting rifles.

There were a couple of "shaving tools" used at point of manufacture / assembly to final-cut the "resisting shoulders" in the body. I have never seen a complete kit, but I suspect there would have to be a hardened "guide-helix", to keep things operating to spec. There would also have been a set of extremely expensive and precise gauges that went with these tools.