Adapt a face plate to an "off the shelf" engine work stand, which gives you a rotating axis _very_ inexpensively.
Some times its easier to rotate the work than move the gun in a circle.

I like industrial grating for the plate material, giving lots of flexibility for clamping the work.

- Add a "timing plate" like a dividing head to improve the radial positioning options.
- Add a 4 jaw chuck to the face plate for odd, small work; or customize your jaw arrangement from there, according
to the type of work you like doing.

FWIW.

--frankb