The screw that tightens onto the mounting block on the back mount (the one with the micrometers) broke. Is this screw just threaded loosely into the aluminum ring or does it have some sort of interference fit that will make it difficult to replace?
Thanks

Sorry we're no help GR577. I've not used those mounts and my books give no clues about the screws.

Could you find some that fit the thread from the bottom and gradually turn down the heads until they fit and hold satisfactorily? If you lack a lathe, holding the thread in an electric drill and applying a file to the head might work.

Though it doesn't get much traffic, asking your question in the Benchrest & Target Shooting forum might get some response.