Algodoo

Luger P08.
To shoot:
1. Pull the mag in.
2. Cock the weapon using cocking handle (grey circle on the top of the weapon) [shame on you if you don't know how to cock the luger ]
3. Pull the trigger.
4. If the mag is empty, remove it just by pulling it out.

Its not very reliable, since it has many moving and colliding parts (whole barrel moves, just like in real one), so patience is welcome.
It likes to misfeed and jamm. In case of jamms, just cycle bolt manually to eject spent case. And trigger works like crap, so sometimes it wont fire, if this will happen, just pull the trigger again.

EDIT: Improved mechanism a bit, so make sure You have the last version (look at the "last edited" line)