I say this from just a lack of reasoning, if it only occurs after the firing pin is fired, and when the bolt is opening, and within that movement the bolt cocks again do not we have a possible spring problem, all the other possible causes would be consistent. If the gun is cocked and you cycle the bolt the "tension" on the bolt lift is not there, that why i wonder about the above idea of the mainspring, who knows who may have been in there, all others I have lift with a finger. This one was not a complete bubba when i acquired it but ......
