Although there isn't a keyed detent on the buried block, there's still a spring loaded ball bearing putting pressure on it. I'd just make sure the little screw holding the inner and outer parts of the gas plug together is snug. Neither the detent or the spring loaded bearing are in a spot where they'd be exposed to carbon buildup (except perhaps blowby around the gas tube with a can). Haven't seen any issues with my buried gas blocks... OTHER THAN LOSING THAT TINY WASHER OR BALL BEARING JESUS CHRIST IT'S TINY. Really though the only parts I've lost forever have been extractor spring detent cap things, they fly! 1.5moa should be pretty easy with quality factory ammo, better if you find something it likes, or hand loadI'm just trying to do some market research. ^-^ Most reviews feature the standard model with the exposed valve and detent as opposed to the buried one. I wouldn't want to drop $2.2K on a gun that FTE/FTFs on me (firsthand experience with the x39 Bren).