I am trying to identify a tool or something I got when I bought out a gunsmith
The large outer ring in 1 X 1 inch and has tick marks on the right side where it tapers. It is .694 ID and 40 TPI the whole length.
The inner barrel is .7135 OD and again 40 TPI. It is 1.13 long and has a set screw and a locking ring. There are two inner diameters; .437 under where the set screw is and .576 for .540 inches on the other side.