Cartridge carrier assembly for a medicament delivery device comprising: - a cartridge carrier adapted to receive a cartridge defining a cavity containing a dose of a medicament, - a needle hub (5.3) adapted to receive a distal end or part of the cartridge, - an injection needle held in the needle hub (5.3), the injection needle having a tipped proximal needle section (5.2) adapted to pierce a sealing element (2.4) distally arranged on the cartridge and a tipped distal needle section (5.1), - a removable needle cap attachable to a distal end of the cartridge carrier and adapted to cover the tipped distal needle section (5.1), wherein in an initial position the needle hub (5.3) is arranged within the needle cap, wherein the needle hub (5.3) comprises a cartridge retention feature (5.4) adapted to abut the cartridge or a part thereof to limit axial movement of the cartridge in the distal direction such that the proximal needle section (5.2) is spaced from the sealing element (2.4), wherein the cartridge retention feature (5.4) is deflectable by the cartridge allowing the cartridge to advance in the distal direction such that the proximal needle section (5.2) pierces the sealing element (2.4), wherein the needle hub (5.3) is adapted to receive the part of the cartridge being a ferrule (2.5) arranged on the cartridge for holding the sealing element (2.4) in position, wherein the cartridge retention feature (5.4) is adapted to abut the ferrule (2.5), wherein the needle hub (5.3) is part of the cartridge carrier or coupled to the cartridge carrier such that the needle hub (5.3) is fixed relative to the cartridge carrier, wherein, when the proximal needle section (5.2) is spaced from the sealing element (2.4), the needle hub (5.3) seals against the distal end or part of the cartridge received therein, characterized in that the needle cap prevents deflection of the cartridge retention feature (5.4) by the cartridge when said needle cap is attached to the cartridge carrier, wherein a blocking feature (5.5) is arranged on the needle hub (5.3) substantially radially outwardly from the cartridge retention feature (5.4) adapted to outwardly abut the needle cap, wherein - the blocking feature (5.5) has the form of at least one radially outwardly directed protrusion or a series of circumferentially arranged radially outwardly directed protrusions or an outwardly directed circumferential rib adapted to radially abut the needle cap, or - the blocking feature (5.5) comprises an outer surface of the needle hub (5.3) adapted to outwardly abut the needle cap. - a cartridge carrier adapted to receive a cartridge defining a cavity containing a dose of a medicament, - a needle hub (5.3) adapted to receive a distal end or part of the cartridge, - an injection needle held in the needle hub (5.3), the injection needle having a tipped proximal needle section (5.2) adapted to pierce a sealing element (2.4) distally arranged on the cartridge and a tipped distal needle section (5.1), - a removable needle cap attachable to a distal end of the cartridge carrier and adapted to cover the tipped distal needle section (5.1), wherein in an initial position the needle hub (5.3) is arranged within the needle cap, wherein the needle hub (5.3) comprises a cartridge retention feature (5.4) adapted to abut the cartridge or a part thereof to limit axial movement of the cartridge in the distal direction such that the proximal needle section (5.2) is spaced from the sealing element (2.4), wherein the cartridge retention feature (5.4) is deflectable by the cartridge allowing the cartridge to advance in the distal direction such that the proximal needle section (5.2) pierces the sealing element (2.4), wherein the needle hub (5.3) is adapted to receive the part of the cartridge being a ferrule (2.5) arranged on the cartridge for holding the sealing element (2.4) in position, wherein the cartridge retention feature (5.4) is adapted to abut the ferrule (2.5), wherein the needle hub (5.3) is part of the cartridge carrier or coupled to the cartridge carrier such that the needle hub (5.3) is fixed relative to the cartridge carrier, wherein, when the proximal needle section (5.2) is spaced from the sealing element (2.4), the needle hub (5.3) seals against the distal end or part of the cartridge received therein, characterized in that the needle cap prevents deflection of the cartridge retention feature (5.4) by the cartridge when said needle cap is attached to the cartridge carrier, wherein a blocking feature (5.5) is arranged on the needle hub (5.3) substantially radially outwardly from the cartridge retention feature (5.4) adapted to outwardly abut the needle cap, wherein - the blocking feature (5.5) has the form of at least one radially outwardly directed protrusion or a series of circumferentially arranged radially outwardly directed protrusions or an outwardly directed circumferential rib adapted to radially abut the needle cap, or - the blocking feature (5.5) comprises an outer surface of the needle hub (5.3) adapted to outwardly abut the needle cap.