Couldn't you take a file, and file the last 1/2 or 3/4s inch of the barrel to the major diameter of the thread size, and then carefully start the die with one of those nice speed squares you get at the depot. The die is tapered so it doesn't cut 100 percent threads on the side you start with, so when the die hits the shoulder you would have to reverse it to get the threads cut full all the way to the shoulder. I think if you had a good pair of glasses and were careful you could do it.