Re: Hornady OAL gauge ????
It can be done but the thread specs are not common or easily available. Forget what it is but having Hornady do it would probably be cheeper than buying the tap.
Since the threads COULD just as easily be conventional I suspect they do that odd size to trap us into buying the silly things from them. I quite using it, went back to the old method of a marked (dowel) rod. It's just as accurate as the Hornady tool, actually easier to do and a dowel costs less than a buck.
I do use the "case headspace" tool tho, it works well.