Aside from the fact that we've been discussing chambers not chokes here's a quote from a fairly well respected shotgun smith Mike Orlen:
"To lengthen a chamber and/or a chamber forcing cone by hand, you will first need to secure the barrel in a bench vise. I like to use a couple of pieces of 2- by 4-inch lumber and an old shot bag to pad the vise. Make sure the barrel is held very tightly in your vise because there is a great amount of torque exerted during this operation.
"With a well oiled and sharp long forcing cone reamer, begin cutting your new chamber by turning the tool clockwise. You will be amazed at how quickly a sharpened tool begins to remove material. After cutting no more than 3/8 inch, remove your reamer, brush off the chips, push a patch through the bore, re-oil, and resume cutting. Always rotate the reamer in a clockwise direction—even when removing it from the bore."
The entire article can be found here:
https://www.gun-tests.com/special_re...l#.XS2tI-hKi70
Threaded Mode