My son is using one in a Adam's Arms piston system but hasn't shot it enough to give a report yet. He is only using the roller cam pin and not the gas key.
I bought the set and have played with it just a tiny bit as I have spare bolts. I found that the notch in the gas key still does not allow the roller cam pin to slide into place. I had to take a file to the gas key and open it further to allow the pin to drop into place and allow removal.
I have not torqued the gas key down and tested it yet so can not give any more information at this time.