Contact Pins

How far have the contact pins been designed to protrude for spring loading contact? I have noticed that the middle “common” pin appears to be recessed almost flush on my unit.

Please refer to link below of photo:

Photo showing middle pin

This is mine.

The middle pin is like that by design, there’s nothing wrong with your unit. That pin is supposed to connect to the side of the reader/key, to there’s no need for it to protrude (as it would only make it easier to break off)