You do realy need more materials than some glue and toilet paper rolls. But to start, as some have suggested, start small with the AR and work your way up. A NF would do a nice start.
No, it's your dart tooth. I don't thinkk it's fixable though. I have this same problem with my recon. The dart goes over the dart tooth rather than being oushed to the back of the bolt.
This is what I was thinking. As someone said before the dart isn't going very far because there isn't any pressure behind the dart. This means that the dart needs to go farther in the bolt, and that is what the dart tooth is for. It would better to get some pics up to see if we can noticer your problem.