https://www.youtube.com/user/RyeOnHam
He has some slightly long winded but detailed videos regarding the R51. His videos on the gun are by far my favorite. I haven't shot mine yet, but after watching his video, I confirmed that I can pull the trigger while the gun is out of battery on my R51. This behavior caused RyeOnHam some issues while at his local range.
Another video (long) of someone having problems with their R51
http://youtu.be/1TSZmkJMBBk
I just hope that the gun runs well for me when I get it to the range.