Here we are so far (upsidedown in the vise).
http://forums.lugerforum.com/lfupload/dcp01224s.jpg
The slots cut so far do not go all the way through. I left about an 1/8" to help support the piece as additional cuts are made. When I am all done milling I will cut through the remaining material with the bandsaw to remove the extranious material. I thought about bandsawing the whole thing, but I think I would have ended up going through a zillion bandsaw blades.
The next cut will be a 3/16 mill right up underneath the lever axle hole. I will then set the vise at an angle and free up the inner section and mill out the "web" on the back inner side. I think I will make my webbing a little thicker than the original. I will then set the bar on it's sides and use a 3/8" mill to narrow the stock tangs.
The arc will be cut to approximate shape by nibbling with a large mill. I will then hand grind the curve to final shape as I test it against the back of the gun.
Down the road a ways, I will have to mill the lug slot. This will be the most difficult part. I'm still thinking about different ways to do this.
More importantly, I find myself wondering how the originals were made. Mass producing these with a CNC machine today is trivial (wish I had one! Someday...). But what kind of fixtures and techniques did the old timers use? I'm guessing they had a big custom cutter that they pushed the front into that cut the whole arched portion with the narrow slot and beveled th edges. They then must have used a radius fixture to cut the t-slot. But for the inside, they must have had to mill it out like I'm doing.
...and mills to go before I can sleep...