Guntec USA AR .308 Muzzle Comp w/QD Blast Shield Black Nitride. The reason for this is the barrel lengths of AR rifles have increased over the last 10 years or so. Guntec muzzle comps are designed to reduce muzzle blast and sound in order to improve the shooters shooting performance and experience in the field or at the range. Guntec muzzle comps work on any AR style rifle or pistols even pistol clones. These compensators are designed to work with cartridges like .308 Winchester and .300 BLK cal reducing the felt concussion in close quarters. Guntec offers a full line of Muzzle Brakes & Compensators as well as a full line of GUNTEC Muzzle Shields. GUNTEC Muzzle Compensators effectively reduce muzzle blast to the shooter's forehead. Guntec muzzle brakes work on any AR style rifle or pistol although they are designed primarily for AR type pistols. Specifications for Guntec USA AR .308 Muzzle Comp w/QD Blast Shield: Manufacturer: Guntec USA Color: Black Nitride Projectile Caliber: .308 Caliber Gun Model: AR-10 Included Accessories: QD Blast Shield Condition: New Features of Guntec USA AR .308 Muzzle Comp w/QD Blast Shield Muzzlebrake & Blast Shield Are Steel QD Blast Shield Threads Down Over Muzzle Comp Nitride Finish 5/8 x 24 Thread 300 BLACKOUT/.308 Cal Reduces Felt Concussion In Close Quarters Great For Use On AR Pistols Total Weight: 9.5 oz (Muzzlebrake and Blast Shield) Length: 2.5in O.D.: 1.5in Package Contents: Guntec USA AR .308 Muzzle Comp w/QD Blast Shield What firearm models does the manufacturer say Guntec USA AR .308 Muzzle Comp w/QD Blast Shield is compatible with? The manufacturer says that Guntec USA AR .308 Muzzle Comp w/QD Blast Shield is compatible with AR-10GUNTEC USA SPITFIRE-308: AR .308 Muzzle Comp w/QD Blast Shield Black Nitride