Just got my new cdnnsports.com magazine and they have blackout uppers for 399.00 go to cdnnsports.com to check them out plus they have lots of other deals too
I have a friend who built one in an 11" SBR and it looks sweet. He ran a .308 can yesterday on his 16" with some 220 grain subsonic rounds and said it was great. Said it sounded like shooting an MP5 with 148gr subsonics with the integral can. He is now making a dedicated can for it.