There are certainly no Machine Shops around here anyway, capable of making a Spring, Capable of Forguing or Tempering or anything really, all they do is squint at a Cad Cam Mill and 'billet' stuff.
Any competent general Blacksmith could make a Spring, long as his competence extends to Tempering as well as Forging simple things.
If you can not find anyone locally to do it, I'd do it for you, but I'd need the old one to copy, which would be easy to Mail, and, some detailed images of where it goes, so far as possible anyway.
I know the Frames on these hide much of where it goes...so...
Do you have all of the parts of the broken Spring?
Can you post some images of the Pepperbox, and, close ups of the interior Grip area?