NEW FN SCAR 16S 16" STAINLESS BLACK BARREL IN 300 AAC BLACKOUT. TWIST IS 1in7. COMES WITH MANUAL, LOCK AND 30RND MAG. HDD DEVELOPED THE 300BLK FOR USE IN THE SCAR PLATFORM. THE HDD 300BLK BARREL HAS OUR HDD HI-TORQUE GAS BLOCK SO ACTION CYCLING WITH SUBSONIC AND STANDARD AMMO IS RELIABLE. GAS REGULATOR HAS THREE POSITIONS, 1. SUBSONIC AMMO, 2. STANDARD AMMO, 3. OFF OR STEALTH POSITION FOR NO ACTION NOISE WITH SILENCER ATTACHED. STEALTH POSITION IS DESIGNED THAT UPON FIRING THE ACTION CRACKS OPEN ABOUT 1/4" , THIS IS SO THE OPERATOR CAN RECHARGE EASILY AND QUIETLY. THE MUZZLE THREADS ARE 5/8X24. FRONT SIGHT IS A QUICK DEPLOY POP UP SIGHT BY MAGPUL® . SELECT OPTIONS IN THE DROP DOWN BOXES INCLUDING FDE OR BLACK FINISH.