Have the same "problem" - with some of my atty's the bottom goes all the way in, and with others, it sticks out. got used to it and more than forgave it, because it is by far the best mech I've used. Performance is amazing.This one has a strange center pin, it slides inside the insulator. If you undo the cap and screw the atty in all the way then the pin sticks out more this in turn then causes the botton section to have a bigger gap when you screw that end on
PS - actually just noticed yours is a Manhattan, mine is an Apollo. I think yours is a better design.