I have an AR-15 in .300 Whisper that I built from scratch about 10 years ago. I use an AAC .30 cal. Cyclone on it. With subsonics all you heard is the buffer weight and spring. I use it on an AAC Micro 7 in .300 Blackout and a T/C Contender in .300 Whisper also. I load 167 gr. to 220 gr. bullets.
I have picked up some 168 & 178 amax's. I'd love to see your load data!