Think of it as a gradual taper in diameter from the chamber to the muzzle.
A heavy barrel maintains the same relative diameter from one end to the other for increased rigidity. A government profile barrel has a dramatic reduction in diameter just past the chamber to reduce weight and promote faster cooling. The target profile is a sort of blend of the two profiles to incorporate the benefits of each...
It is hard to tell with the handguard being so much bigger in diameter. But it did not look like a pencil barrel. I wish someone had one in stock. Closest is Gander. About 25 miles away. I may have to call them and take a drive if they have one.Haven't handled one and I can't seem to pull up any definite specs, but from all the images I've seen it's definitely not a pencil barrel. Looks more like a medium bull to me...