I had the same thing in my Knight Long range hunter when i got it. It was just at the tip of barrel. It also had alot of sand in the barrel stuck to the grease they shipped it with, the people at knight said it was from blasting the pretty finish on the outside of the barrel and it just hit the inside, it never affected accuracy.

It was a great shooting gun, until you took it apart to clean it, and the point of impact was never the same. Then another LRH owner told me to put my gun in a vise and watch through the scope and tighten and loosen the lug and forend screws and watch the crosshairs move. He then advised me to purchase a bore sighter, and install in the barrel and see where it was lined up, and make sure it was the same whenyou put back together. After that no problems...........

I would just run some Flitz Polishing Compound on a few patches and see how that does.