M249, MK46, MK46A1 CALIBER CONVERSION KIT TO 300 AAC BLACKOUT. THIS KIT CONSISTS OF A 18.5" BARREL ASSEMBLY IN 300BLK.

1in7 TWIST, MUZZLE THREADS ARE 5/8X24. (THE STANDARD 5.56 M27 LINKS RUN THE 300BLK)

THIS BARREL IS ALL YOU NEED TO CONVERT TO 300BLK.