I’m very good with this gun, and I’ve run into something similar.
first off, the extractors. There are two rods that sit on the sides of the body, they have curved ends to capture and divide the magazine pay-out.
if the magazine tube has been extended, the tube spring may not have been replaced. This too I have run into that prevented the next round from ejecting from the magazine into the loading cradle.
If you need specific descriptions, pictures or video please let me know. I would be happy to provide it.