Lens feels stiff when mounting?

I just got a 16-35 f/2.8 II lens today, and when I mount it to my camera it feels stiffer/less smooth than when I mount other lenses to my camera body. Is this normal? Anyone else have this issue?

Sometimes the mount is loose, sometimes tight. As long as it goes on and clicks into place, I would not worry too much. But you might just check the mount for any dings, dents or loose screws. Was a thread a while back where a mount screw had come loose while mounted and the lens would no longer come off. Not sure how it got resolved. But if all looks fine, I wouldn't worry too much.

Cool, thanks.

It may get better as the O ring ment to keep rain out wears in.

Sounds normal, if not try a bit of lube.