Pleasure, Ed. Almost 'fixed' the small neck on mine with a chucking reamer - from Pacific. They used to be quire reasonably priced and are available in .001" increments, I think. One of the guys on Saubier's Small Bore Forum used one on a job he was doing where he only had to enlarge the neck to an appropriate size.
Since mine shot so well with normal 9.3 bullets, I left it as-is. However, if wanting to shoot cast bullets accurately, it would need to be enlarged to hold a .370"(minimum) to .372" (best) bullet.

Incidently, a lee lead bullet sizer die will reduce jacketed or cast .375's to .370" or .372" in one pass. They now have this technology and are making dies for guys for doing just this, sizing down over-sized bullets to fit their rifles. They do suggest .003" increments, I think. This move with Lee, thanks to Rod Halversen of Idaho.
Cast bullets can be sized down easily and perfectly, as long as they are properly lubed first. I have sized .376" down to .366" with excellent results - no distortion and great shooting (in my 9.3x62).