Armedsask said:The rifled portion of the AR180B barrel is 18.25 inches, and therefore too short.
The only reason it isn't resricted is that the muzzlebrake is integral to the barrel and brings it over the 18.5 mark. The threaded AR180B barrels from Armalite are restricted and always will be.
We that have threaded our 180B's have let that extra 1/2 inch of the muzzlebrake material on to keep it legal. Either that or we just keep our mouths shut.
What was said above period.