I shot Steel challenge today with PCC. Gun is a QC10 (upper, lower, barrel and BCG) and ran perfect with a variety of ammo but on the last 5 shots of the match I had to manually cycle the bolt before I could shoot. I looked into it a bit further when I got home discovered that the hammer wasn't releasing when I pull the trigger. As it turns out, there was buildup on the dual spring assembly which prevented the trigger from releasing. I removed everything, cleaned it and reinstalled it and all is good now. I'm using the heavy springs(which provide the lightest trigger pull). I wonder if the medium or light springs would have still allowed it to function. Anyone else have a problem like this with Hiperfire?PCC is dirty and I'm wondering how often folks clean the inside of their lower. Prior to this match I had about 1000 rounds through it with the 243G installed so I sprayed some brake clean in the FCG without removing it and blew it out with air.