If I own it, it must be threaded. Barrel, bolt, whatever..... that's just how it is when you have a lathe to play with.
I just bought an Axis to build on, so had to make a jig for the bolt handle. I think it turned out pretty good. It's threaded 5/16-24 and I also made the knob. The handle is slightly ovaled where the existing knob was, so can't really get a true seamless fit. Overall I'm happy with it.