Originally Posted by
goodsteel
That explanation needs explanation!
I don't see how having an octagon barrel gives you any advantage over a round barrel of the same diameter as the measurement across the flats, especially because the barrel flats do not "twist" with the rifling.
I've never heard of this as being definite fact, but I'll take your word for it.
Could you elaborate on this a little bit? I know what a rifling bench is, and I assume that the "rifling engine" is the automated sort that was driven by the overhead mandrel in old factories. I have studied the rifling process lightly, and I was under the understanding that cut rifling required one set up to align the barrel with the axis of the cutting rod, and simply rotating the barrel to cut each groove a few ten-thousandths of an inch deeper each time. I would not really call each time the barrel is indexed a "set up" as it required nothing more than pulling the indexing pin and rotating the barrel 45 degrees and repeating the cutting process. If you are referring to some process other than using a sine-bar rifling bench, I would like to know what it is and how it works.