Yup. How did you lose it?
I have no idea, when I first got the gun a couple weeks ago I noticed the clip was just slid over the pin and not in the Grove of it. So I put the clip back in the groves of the pin and I just noticed lastnight that it's now missing
Sounds like the original C clip was not tight. You can probably get them anywhere for cheap. Maybe buy a few just in case? At least it's nothing serious. On a side note, maybe now is the time to change out the dust cover to something really cool. Most new dust covers come with a new C clip. Just a thought
Maybe one of these?
http://leoarmory.com/ss/images/products/large_304_IMG_0101s.jpg