Is the length of the 100-400L fixed?

I'm hoping you 100-400L owners out there can give me quick answer.

I've just purchased a new bag, and I am trying to see if my next purchase will fit while I still have time to return it. My next lens will probably be a 100-400L. I am am trying to find the SHORTEST length the lens has to see if it will fit in my new bag. I see that the max length is 7.4 inches. I seem to remember that the overall physical length of the lens does not change- only the elements inside the tube move. Is this the case?

If not, what is the MINIMUM physical length of the 100-400L?

Thanks.
JT