Dueling M5 AR308's ? I've test-fired my 20" barrel .308 factory Aero, but haven't got it sighted-in yet !Picked up my new Aero Precision M5 AR308 yesterday. Cleaned the factory preservative out of the barrel tonight and removed the handguard to replace the birdcage flash hider with a Rugged suppressor mount/brake. Got it all finished up and had everything in my hands to carry back upstairs when I noticed I had eff'ed up and put a 3 pronged suppressor mount on. Oh well, I called it good practice and put the brake on.