The history of SLAP round development is full of mishaps like the one above, but in much more carefully controlled and safe settings. I would be surprised if his data was exactly correct, and an operating pressure of 55KPSI was both safe and expected, yet 85KPSI spelled disaster. Not enough safety margin. Bullets striking 18" from POA at such a short distance was a real clue that something bad was happening in the bore. Anyway, I have seen his YT channel, and he is not a nut case at all, but quite an articulate and well informed guy who made a mistake. A nearly fatal mistake. Anyone forget their safety glasses from now on? Didn't think so .......valuable lesson, thanks for posting......FWB