1 A gun store employee telling a customer who wanted to buy an AR15 with a piston upper: “Those are unreliable. The piston is just one more moving part that can break. The beauty of the gas tube is that there are fewer failure points.”
2 Another employee who told me that the M&P40 cannot be converted to fire 9mm. The only calibers that the M&P40 can fire are .40S&W and .357Sig. I told him that Storm Lake and KKM both made 9mm barrels for the M&P40. He said I was wrong. I left the store.