Wow! 150 out of 200. That sounds like "grip sensitivity" stuff. Decades ago I read Cooper's article describing this. It was hard to believe until my parachute rigger, a guy named Earl, turned out to have it. It wasn't "limp wrist" either. Earl could take my own Combat Master in a two handed "vise grip" on sandbags and get malfunctions nearly every other round. I would then load up the same cartridges and shoot every which way, including upside down left handed, two handed between my legs, fast, slow, you name it, and never have a problem. Then Earl would try some other grip. It just didn't matter; my otherwise flawless Combat Master would jam in Earl's hands almost every shot, and never jam in mine. I quickly realized that Cooper was right; this phenomenon really does exist. It's an amazing thing to witness in person. Almost like Voo-Doo or something. I've yet to witness it with a Detonics USA CombatMaster, but I wouldn't doubt that guys like Earl could make it happen. (By the way, what was the name of the guy you read about???)
...Deeton