SI Defense Barrel AR-15 300 Fireball (7.62x35mm) 16" M4 Contour 1 in 8" Twist Matte

Product #: 677048 SI Defense #: SI AR-15-B-M4-300BLK-16
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  • Information
SI Defense AR-15 Barrels are made from 4140 chrome moly steel and use button rifling. The barrel is chambered in 300 AAC Blackout with a 1 in 8" Twist. The M4 profile is light under the handguard and .750" at the gas block with the M203 cut. The muzzle is Threaded 5/8"-24 to accept muzzle brakes, flash hiders, or a sound suppressor. The barrel is finished with a mil-spec manganese phosphate finish and includes a pre-installed barrel extension and locator pin.

The 300 AAC Blackout (7.62x35mm) squeezes 30 caliber firepower into the traditional AR-15 envelope, and is available in either subsonic or supersonic ammunition varieties to serve a multitude of purposes. All that is needed to harness the enhanced performance of the 300 Blackout is a simple barrel swap; the bolt, carrier, magazine and all other components remain the same as those used in a traditional 223 Rem/5.56 NATO rifle.

Technical Information:
  • Length: 16"
  • Material: 4140 Chrome Moly Steel
  • Contour: M4
  • Chamber: 300 AAC Blackout (7.62x35mm)
  • Twist Rate: 1 in 8"
  • Chrome Lined: No
  • Finish: Mil-Spec Heavy Phosphate
  • M4 Feed Ramps: Yes
  • Muzzle Thread Pattern: 5/8"-24
  • Gas Port Location: Carbine
  • Exterior Diameter at Gas Port: 0.750"
  • Gas port comes set for supersonic ammunition. It may need to be enlarged to fire subsonic ammunition.

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