I received another magazine the other day and hoped that things would be different, but I wasn't. The HK417 still wouldn't fire on semi. So yesterday, I went to trigger airsoft and bought a different brand of bbs called Action Army 0.2g and 5.95mm.
Now the gun is firing flawlessly both on semi and auto. It's amazing.
The question I have now is how can I fix it so that it fires other brand bbs. I though that TDS bbs were good. Also, how much difference will using a smaller size in diameter bbs make for accuracy?