I have had issues with this gun for several months now, I replaced the buffer block, then its gone down hill. Either it will not eject, or it will not feed, or it will not pull the next shell into the chamber. I have been looking for a new side plate assembly with everything together so I could just drop it in, but I haven't found one for sale. Do any of you have experience with this gun that might be able to give me some tips on how to get it working again?