In this video, we’ll put the final touches on the upper assembly by walking through the assembly of the Bolt Carrier Group (BCG), checking headspace, and finally installing the BCG and charging handle into the upper receiver.
Note: Here, I show you how to check headspace with the extractor installed. You can also do this check without the extractor installed and have better “feel” for the headspace measurement/check. Note that you’ll have to tap out the headspace gage with a cleaning rod if you go that route.
Next, it’s on to the lower assembly!