My dad recently found his old Ruger 10/22... He's not much of a "gun guy" so I took it home with me to give it a quick look over. I wanted to make sure he had a FUNCTIONING firearm in the house. The rifle was in superb condition on the outside but when I tried to cycle a full mag the rounds failed to eject.
I took it apart and found that the extractor spring was stiff as a board and covered in rust along w/ the extractor itself. I soaked the spring and extractor in Hoppes #9 for a few minutes, whiped them down, and put it back together... Problem solved! (Also added a new bolt buffer, extended mag release, auto bolt release, and polished some of the parts
Anyhow, I'm sure this is NOT your problem, but if all else fails check the extractor. I seriously doubt you have any rust... but it wouldn't hurt to give it a look.