EF70-200mm f4L, problem?

I got a 70-200 f4 L last week but I haven't really played around with it much till today and I noticed something that I wasn't sure about.

I'm still new to the "white" lenses, so I thought I'd ask here before I take the lens back.

I noticed that when in MF mode the focusing ring will rotate beyond the "stoppers," or designated area.

It's OK. All FTM lenses do that. Lens focusing mechanism contains a clutch that disengages focusing ring during AF and when you turn it beyond distance scale.

Yep, perfectly normal.
Enjoy the lens ... great choice.

Thanks for the replies. You made me much happier.

It's designed to do that. It's so you don't damage it when you over rotate the ring.

What's the purpose of the AF "stopper" anyway? So it doesn't have to rotate all the way to the end and come back if it's hunting?

Yes. This switch allows you to chose between two closest focusing distances in order to reduce focusing time and to prevent hunting.