when you say nib do you mean part of the ink refil is sticking out? I am looking at a Vertex Click I just finished and my blank/tube is 2.91". Is yours shorter than that?
The problem might be in the mechanism. I have one in the drawer that never worked no matter what I tried. Between that and the 2 clickers breaking off when it falls on the floor I never touch them anymore.
I had the same problem - thought my tube was short also. I ended up turning a 1/8" band and used it as a spacer and placed it on the threaded section. will not make anymore of them.