Macroimage, It's definitely rougher than any lens I've mounted on any camera before. It doesn't grind, but it does take some effort to put on whereas all my other lenses are nice and smooth.
Edit: Zero, I bought it new at Best Buy. It was the only one within 30 miles of my house in Houston.
FWIW, I bought my 40mm at Best Buy. It went on as easy as all of my other lens on all of the camera bodies I've tried.
I'd return it for one that doesn't take that sort of effort to mount. This is not the sort of thing I would want to get "looser" as you use the lens.

