Sometimes you need to weigh up the time and costs, if you have time on your hands then your saving already, depending where you buy the blank from they will thread, profile and chamber but these add up, Walther will do all these but not for an individual you need someone who has a trade account with them...... but there costs for a profile are peanuts compared to quotes I,ve had, IIRC its around €50, myself I think this is worth every penny.
I have my own Lathe etc but no taper turning attachment so it does take a decade to get a decent profile, don't listen to anyone who says you just off set the tail stock......
Threading is a basic operation, a bit of practice on offcuts etc and you can produce a decent thread, as regards to the chamber its just a reaming operation, if you page down the link below you can see a thread taking shape etc. scroll down to part 5 or post #16. ( I must point out the work was secured with the tail stock when machining the thread, pics show it out of view, this was solely for taking the photo)
SMLE No1 MkV Restoration (Part's 1 thru 7)