Don't be afraid to center your front sight on your Norinco M14s to get it to shoot straight with the rear sight centred. Mine was fully off to one side, and as a result, required the rear sight to be six clicks off in that direction as well to shoot straight. The single hex screw is a 2.5mm and simply needs to be loosened, and you can tap the sight over with a brass drift to center it. I have no idea why mine was delivered with the sight way over to one extreme, and it staked in that position. I'd much rather move the front sight at the range until the gun shoots straight, that way the rear sight mark remains centered, for easy recentering after making windage adjustments.