That’s one pretty killer endorsement of the piston-driven Adams Arms PDW upper — “This is the most reliable upper I’ve ever use, and way more than any direct-impingement has ever come close to.”
Managing 1,700 rounds without a single failure is additionally impressive when you take into account the upper was never cleaned and it was fired suppressed. One of the drawbacks to running a rifle with a can is that the back-pressure dumps a lot more gunk into the system. With the Adams Arms piston system, the gas is vented at the gas block after the rifle begins to cycle.
You don’t have to run a gun in these types of extreme conditions to appreciate the improved reliability. Adams Arms is a big part of the reason why gas piston systems are gaining more and more traction every day.