Just my opinion based on gut feel. No data to back it up. 

I don't think any other process can approach lost wax for economy. 
3D for metal gets used where the parts are  complex and difficult to  do any other way.

The price of Storey's castings should give you a hint on base costs; and he still has to have a decent profit built in. For small volume production start with those castings, contrive a way to index them for  machining and get with it.   Broach or EDM the mortice. 

CNC all the small parts. 

Alternatives:   
Picatinny Arsenal used electron beam welding to fuse halves of some AR's. I suspect the real cost of that operation alone is in the range of $150 each. Kinda ruins the economics.
I think about submerged arc for welding halves together. No proof that one can produce an unwarped part though. Fun to think about but any process takes a lot of development.

A striker Ballard might actually sell well. Looks somewhat like the original and should shoot rather well.   

As an example of modern manufacture from billet: steve earle's Fraser. A lot of EDM and then hand work to finish. $2650 or so just for the action. Also no heat treating!

Just rambling thoughts and a cup of coffee.


As to the low wall Browning; modern metallurgy and some redesign to add metal in critical places makes it much stronger than the originals.