It might be handy if a few people posted the lengths of their various tubes (preferably in mm) so that others may better understand how much variance there can be in the "same" tubes. Something like:
"brand", date of manufacture if known or maybe even purchase, length, capacity with "x" guts and basepad, comments, etc....
ex. STI, purchased new Dec 2011, XXXmm, 19 (reloadable; 20 start) w/ x spring and follower and x base pad, worked right out of the box in my Brand X pistol...