Here is what we know: this is a factory KAC built .308 using a Silencerco suppressor mount on a Proof Research carbon fiber wrapped barrel.  The MLOK rail covers, STR stock, and MIAD grip are all from Magpul.  The optic is a Trijicon TARS (Tactical Advanced Riflescope), and the mount is a dual throw lever manufactured by Bobro Engineering.  The rest of the weapon is all from KAC.  What makes this interesting isn't the non-KAC barrel, optics or mounts (we are all aware that companies use products from external manufacturers based on given requirements).

Nope, what makes this interesting is the .308 MLOK rail from KAC, who supposedly said this rail wouldn't be made.  

Did KAC change their minds?  Did the demands of the public sway them?  Was it an existing .mil customer who wants to switch to the lighter weight MLOK?  Was this all just an in house project for KAC to validate some other program?  We don't know, and the guy with the gun isn't giving up any secrets.  Personally, we think KAC would be crazy not to release the .308 URX4 rail in MLOK, after all, man can not live on Keymod alone.  
Also shown with this black sheep of the Knights family are folders from Mcginnis Custom Knives and Defiant 7.  

Burke Knives

Trijicon TARS optic

Magpul ACS stock, Magpul MIAD grip, and some Magpul MLOK covers.  

Proof Research 

Bobro Engineering mount.  Bobro recently came out as the best/ most repeatable mount in RECOIL testing.  The dual throw lever is used due to the extra weight involved with this scope.  

Gerry McGinnis Custom Knives

Knights Armament Company