I have had a M200 Anthricite, a translucent pen, that came with an extra fine, EF, nib. I changed it to a medium, M, nib, and the medium wrote a finer line than the EF nib. I have sometimes found situations like this with Pelikan nibs. It's kind of amusing. I think I'll continue to use the medium in the hope continued flow of ink will open up the flow. The ink is a very dark Noodlers green. I am not looking for a fix, I was just amused to have a medium gold plated nib write finer than a gold plated extra fine. Both steel nibs. Excitement in Tecumseh, Michigan, during a snow storm.