As my first gun, this is a bit disgruntling. I purchased it back in November, and haven't managed to get to a field with it. The Semi function was working for about 2 months after purchase, and stopped some time in December.
Those times being a couple times when I went to a friend's house for target practice.
The Semi will more often than not cause the Gearbox to go halfway, then stop. In the video below it will go from not working, to working twice, to going full auto.
I've never opened it up. I've been holding off swapping my spring until I can get this resolved (It has an easy access spring anyway).
I was looking for help at TA, but they don't have a Gun Doc yet.
http://youtu.be/daf0erfgL4w