src mp5 help needed

[Robbi3b]

I have an src mp5 I had a problem with the wiring running across the mag slot I have sorted this out, what I didn't realise is a little metal tube fell out and I have no idea where it goes is about half an inch long and not very wide any ideas please many thanks robbie

[TheGrover]

Pics perhaps? Does the gun still cycle fine? Does it shoot well?

 

It may be a pin that held two pieces together, how long is it? How wide is it? Is it hollow? is it painted or coated? Did it have any lubricant on it?

[Samurai]

To the mag release if it's a thin walled, brass one.