While the video 9-Hole put together is featuring a very modern take on a 5.56 NATO AK, the result Henry talks about and shows is something to watch. The run itself highlights what can go wrong, even with good equipment. Sometimes an angel pisses in the powder of your musket.
Stuff can start going wild and fixing it to a working condition to get the job done requires recognizing the signs things are going wild. Sometimes it just exists outside the parameters of you you have because the ammo is a wild lot or load or the rifle made it beyond a certain endurance point.
Anyway, know the signs so you can respond and fix. Whether in the field or on the bench. Remember, EVERYTHING breaks.