BR,
It still interesting to look at those old drawings. Ganging up all those cutters on a horizontal mill is not done any more. I have rarely put more than 2 cutters on a mill arbor and not done 2 at one time in 35 or 40 years. It does explain how all those different cuts could be made and not loose the relationship of all the different features on the receiver and bolts. A lot of the machining could be done on a 5 axis mill today but the program would be thousands of lines long and involve many tool changes.
Someone recently suggested investment casting would be the answer to making new Krag receivers and that is probably the best method for anything as detailed.
If anyone has a scrap receiver and bolt to donate to the cause
I would like to keep them here in the shop to look at.