A composite pressure vessel assembly method includes fitting an end portion of a tubular member into an annular slot formed in an end cap. Sealant may be in the annular slot. The end cap includes an annular groove in an exterior surface of the end cap body portion. A first material layer is formed on an exterior surface of the tubular member. The first material layer includes a first composite material including fibers oriented circumferentially to the tubular member. A second material layer is formed on the first material layer with a portion of the second material layer being disposed into the annular groove, and includes a second composite material including fibers oriented axially to the tubular member. A third material layer is formed adjacent the second material layer and in the annular groove, and includes a third composite material including fibers having an orientation circumferential to the tubular member.