Took the AR pistol to the range yesterday. It had a new BCG installed. Exercise in frustration. Bolt override malfunctions. The bolt works as it's supposed to. It is one of the newer bolts that has the 4 coil spring and the doughnut on the extractor. I replaced the bolt with an older bolt I had on hand and it works fine. I have replaced the 4 coil and doughnut extractor spring with a BCM 5 coil extractor spring. Will see if it works today after the temps climb to at least the double digits.