I Cannot Unscrew the Body From the Nib Section of Visconti Wall Street

[StacyBean]

I just unpacked a lovely new red Wall Street and the body won't unscrew from the nib section. I have two other converter filled Visconti Pens ( Van Gogh Maxi and Room in Arles) and haven't encountered this problem before.
Suggestions welcome.

Thanks!

[StacyBean]

With some reassurance from Bryant Greer that the cause was most likely temperature variation in transit, I used a rubber band was successful.
Now the ink!