I should have 2 samples ready to send to Jon early next week for fitting and testing. Also getting closer to a price. The hold up on that is quantity. But it looks to be well under 10 dollars a piece for brass. The samples will be based on Jon's design with a straight 21 mm OD. No step down. Top will be threaded for the cap and the bottom will be a 9mm bore hole per Jon's prints. Interior dimensions per Jon's prints.
About a half dozen folks have said OK. Please check the drawings Jon made using the emachineshop program. It's a free download. That is the one I am having made minus the step down on the OD. It is important that everyone knows that. I do not want to make 40 - 50 pairs only to find out that not everyone is cool with this design.