A nib assembly for a writing instrument comprises a ferrule having a first end and a second end. The ferrule includes an inner ferrule wall and an outer ferrule wall, the inner ferrule wall and the outer ferrule wall being separated by a well having an opening. A cap has a first end, a second end, and a first cap wall. The first cap wall is sized and shaped to be at least partially received within the well, the first cap wall being disposed at least partially within the well, between the inner ferrule wall and the outer ferrule wall, when the cap is coupled to the ferrule.