So my friend gave me his Bersa Thunder .380 to try to fix. The slide is locked closed, it won't even budge. There is no round in the chamber, and the action and safety still work, but the slide is locked completely shut. It won't budge, not even in the slightest. It's got a little very mild surface rust here and there, but I'm not sure there's enough that the slide would be rusted to the frame. Is there anything else that might be causing this problem? Thanks.