[aznpos531]

The bolt assembly has 2 pins that sits on springs and the bolt handle that inserts into the bolt assembly has corresponding dents that line up with the pins (the pins keep the bolt in the up or down position). There are 2 common problems that I've noticed with my Well L96 bolt:

1) The bolt assembly and handle are made from crap metal and deforms very easily where the pins are a harder brass-like material. If the dents have been deformed, the pins no longer line up properly and the bolt gets stuck.
2) Also, as you mentioned, if the bolt handle starts to get loose, sometimes the pins will fall out of the hole and get stuck between the bolt handle and assembly. If you move the bolt when this happens, you'll cause problem 1.

Open up the bolt assembly and check to see that everything's fine. If it's all damaged, the only thing you can do is order a new one. I believe that Guarder makes one.

edit: When I have time, I'll take pictures of mine to show you what I mean.