Auto injector with cartridge locking system

A system comprising an auto injector and a cartridge assembly comprising at least one cartridge retention member, wherein the auto injector comprises:

• a housing;
• a cartridge receiver with a cartridge receiver compartment configured to receive the cartridge assembly comprising the at least one cartridge retention member, when inserted through a cartridge receiver opening along a longitudinal axis in a receiving direction;
• wherein the cartridge receiver has a passage through which the at least one cartridge retention member travels at least in the receiving direction, and a member preventing movement beyond a retention position in a direction opposite of the receiving direction;
• an elongated ejector that is configured with:
• an ejector support face for supporting the cartridge assembly, a longitudinal ejector slot extending towards the ejector support face from an ejector rest portion;
• wherein the elongated ejector is suspended to move along the longitudinal direction and is spring-loaded in the direction opposite of the receiving direction;
• and
• an ejector lock rotatable relative to an end of the elongated ejector opposite the ejector support face, the ejector lock supported for turning at least a fraction of a revolution and maintained in a longitudinal position relative to the housing;
• wherein the ejector lock has an ejector lock support portion that is configured to align with and slide along the longitudinal ejector slot at a first angle and to be brought to align with the ejector rest portion at a second angle.