Hey, Bill,
It's been a few years since I watched the tape, but I believe "The Gunsmith of Williamsburg" has several fairly good views of the rifling machine they have out there. I have been there and watched them do a portion of the rifling process. Contact me via PM and maybe we can get together to look at it.
It does cut only one groove at a time and removes very little metal from the groove with each pass. The barrel is indexed to rotate for each groove of rifling, whether it's 5, 6, 7 or whatever. If you don't have a lot of time, this method isn't the way to go.
It's been a few years since I watched the tape, but I believe "The Gunsmith of Williamsburg" has several fairly good views of the rifling machine they have out there. I have been there and watched them do a portion of the rifling process. Contact me via PM and maybe we can get together to look at it.
It does cut only one groove at a time and removes very little metal from the groove with each pass. The barrel is indexed to rotate for each groove of rifling, whether it's 5, 6, 7 or whatever. If you don't have a lot of time, this method isn't the way to go.