Ok, here's my update
I had three issues to deal with.
1. The "elevator" or carrier was not working,
2. The magazine would not feed the rounds,
3. The fired shells would not get extracted.
Let's just say that nothing was working.
1. for the carrier: I removed the trigger assembly (you just need to punch two pins out of the receiver) and realized the culprit was a stuck plunger as mentioned in my previous post. I had to use a dremel to file a little bit of the surface of the plunger and its cylinder to free it. I cleaned and very lightly honed these parts and it's working ok (for now anyways). Here's a picture of the plunger and spring finally removed from their hole:
2. The feeding of rounds from the magazine was a bit more involving. When I inspected the receiver, I found that one of the grooves in which the two arms of the slide were suppose to slide showed some damage. I'm still puzzled as for the cause of this. Anyone having insight is more than welcome to share their thoughts.
Here's a picture of the section that was bent (after I straightened it). That picture is taken from the bottom, with the trigger assembly removed. The circled part was bent downward and kept the leaf spring from retracting in its track, preventing the feeding of a new round (and making any movement of the slide very difficult...). The gun is pointing to the left. I used a chisel to unbend it and used a dremel to finish the work.
Even after this, the rounds wouldn't feed out of the magazine. I found out that the point of contact with one of the slide's arms and the leaf spring was buggered up (and badly machined to start with). Here's that part of the slide arm after it's been corrected:
3. Finally, the extractor: it was all dull and badly shaped. I used the dremel again, gave it a more "biting" shape, and the gun is now extracting the shells properly (Haven't fired them yet though).
I hope it'll still do after I try to fire a round with it... I think I'll do it with a string from a distance!
The more I play with that gun, the more I see differences between a $130 gun and a $250 gun
Hope this helps,
Lou