Another note on this gun is the tang screw that attaches the stock.  I don’t know but maybe all Hepburns use the same style attaching screw.   

There is only one screw and it is tapered. Looks to be a #4 taper or very close to it.   First one I have ran into like this.
Bob

Using the same concept as the 3D drawing (video), I wonder if the receiver could be fixed to a vertical rotary table, with the scraper locked into place  in the spindle.  The mill knee could be used to feed the receiver into the scraper, then the rotary table could be used to rotate the receiver to make the radius cut.

Bob
Of course you can also have a copy of the 3D model if you want. I do not know if you have CAD software. I use Fusion360 but can export as a STEP model also.

AJ wrote on Nov 6^th, 2024 at 10:03pm:

Yes I think that would work. It would be slow and tedious but save having to make alot of special tooling, other than the  cutter itself. I would make the cutter so it only scraped one radius at a time so as to reduce force needed. Cranking that rotary table handle may get old really fast. Rigidity of the cutter sticking out of the quill could be concerning. Make it as beefy as possible and consider making the actual cutting edge using a carbide tool insert. 2 things with that, if the scrapper dulls just replace the insert and saves on a rather large piece of high speed steel being needed for the cutter. But lots of possibility in this concept.
Another challenge would be constructing the mounting of the action body onto the rotary table such that it is aligned and that the center of the 1 1/8" matches perfectly with the center of rotation of the rotary table. Not impossible but not easy either.

TomKlinger wrote on Nov 7^th, 2024 at 4:25am:



Tom, the frame is all one piece.
Bob

Bob ,
     I think you got enough of us dimbulbs that it made a bright light on this problem. Brainstorming works. I have a receiver Casting that I will try this on. But as you say, I will rough out as much as possible with a long end mill. Before using the rotary table set up. I will say it again I really like your builds  you take the time to share with the rest of us.

Bob stated earlier:
"I think the key to using this method* is removing the bulk of the metal using a different method..... " 
*(current rotary scraping idea)

I think I would do this with an end mill (could be at first a diameter of 1/2" or a little larger even, for rigidity, then again using a small diameter to refine the shape) and make a series of calculated X-Z moves such that the cutter cuts/inscribes a series of stairstep cuts removing the bulk of the material. Trying to swing in the radius shape on a vertical rotary table would require a very long, small diameter end mill. Although the number of required steps would be quite a lot the math of the moves could be generated on an Excel spreadsheet quite easily, there by easing the tedium of those calculation and greatly reducing math errors. (been there done that ) Once the major material is gone the scraper either on a dedicated swing tool as I earlier suggested, or the AJ method using a vertical mounted rotary table, would have half a chance of working.  OR burn it in on the EDM and be done with it