M4 lens doesn't fully rotate

Hi all, I just purchased an M4 with a collapsible 50mm Summicron. And I've been having a problem mounting the lens, wanted to see if anybody had the same problem with me.

 

Basically the lens doesn't rotate until it clicks, instead it gets stick right before it reaches the end. The Dropbox link below has photos of where it stops, and inside of the mount.

 

Dropbox - m4 - Simplify your life

 

 

 

I'm going to take it to a repair shop on Monday, but wanted to see if this is a simple problem that I can solve tonight so that I can take it out tomorrow.

The pictures show the lens being mounted in the collapsed position.

 

What happens when you extend the lens into shooting position and then mount it?

Its still the same.

Is this the only lens that will not mount on the M4? If so- it is likely that the mount of the lens is damaged. I had this happen with an LTM to M adapter ring, an original Leica adapter.

This is the only lens I have right now. I've been taking a look at the lens mount and there is an odd bump that looks like it's stopping the lens from fully rotating. I guess I have to take this to the repair shop tomorrow. Thanks Brian.