Have at it fella's

https://youtu.be/J3pDlKxou6Y

I can see this guy setting up shop on the Kyber Pass to do AK barrels. Pretty ingenious though.

An interesting video. I have been toying with the idea of building a CNC cut rifle machine from a scrap lathe. Too many ideas....not enough time or money.

Fancier than the one in my "Foxfire" book...

Too bad he has so many comments/questions and no answers for any of them!
Interesting project.

Shilen isn’t much more complicated. They pull the button through spinning the barrel and using a hydraulic ram pulling at consistent speed. Their contraption looks pretty similar though.

Couple of comments;
You can buy rifling buttons on eBay for $16. Those, and the way he did it, rely solely on the helix of the button to create the twist.
That is the cheap way to do it as it requires only a hydraulic ram. The guy in the video spent a lot of effort making the rod supporting mechanism.
However, the best, and most accurate way to button rifle is to do it like Douglas does. The rifling button is pushed though, and it is Gear driven to insure uniform twist rates. That is the reason they only offer whole inch twist rates; they use old school, hard gears to insure the uniformity of twist.
Well proven method.
Of course, reaming and stress relieving is vitally important too.
The video might put grooves in the tube, but there is a lot more to making n accurate button rifled barrel.
Which is why I only use Douglas Barrels, and yes, I have used all the others, except for that one which shall remain nameless.