I bought the ATH and love it ! It is amazingly accurate ...after some load development it shoots the 60gr Vmax well under a half inch ...I have one target I shot at 200 yds 5shots .600 CTC..I can't believe how accurate it is !
Mine was not noticeable until my last range session. And then again it was a light amount of blowby. Once I tighten up the gas block and clean it off I'll try shooting some more and report back to yo what I find.
Thanks for posting your confirmation.