Ah, one of my favorite slo-mo videos. I have used that video in the past to support my argument that AKs don't need a recoil buffer. If you notice the bolt carrier makes contact with the rear trunnion less than half of the time, when it does it still doesn't look too abusive. With a fresh recoil spring the action is buffered plenty. My theory is that a buffer could actually accelerate wear on the locking lugs and recesses due to being sent home with more speed than a recoil spring alone. It may not hold water and may never be tested but thats my story and I'm sticking to it.
Sorry to get on a tangent and derail the thread, just one of those things.