A cartridge holder assembly is provided, comprising an enclosed cartridge, a distal portion and a proximal portion. The enclosed cartridge defines a longitudinal axis and comprises a generally cylindrical main portion, a distal outlet portion having a neck portion with a circumferential shoulder portion, and a proximal portion having an opening surrounded by a circumferential rim. The distal portion comprises a distal support structure engaging the cartridge neck portion and being adapted to support the cartridge against movement in the distal direction, and the proximal portion comprises a proximal support structure engaging the cartridge circumferential rim and being adapted to support the cartridge against movement in the proximal direction. The proximal support structure is essentially non-deformed, and the distal support structure engaging the cartridge neck portion is plastically deformed.