I read the various threads about the BCGs and their differences. Between BCM and Noveske, the main differences is that BCM tests every bolt and Noveske batch-tests. Additionally, the extractor set-ups are different: coil count and insert colors, blue vs black. My question is: if I can use either BCG in my personal defense rifle, is one better than the other? I own an N4 (defense) and a BCM 20" rifle (range). I could exchange BCGs if warranted. Thanks in advance for the advice.