Method of manufacturing a sub-assembly of a medicament delivery device

A method of manufacturing a sub-assembly of a medicament delivery device, the method comprising:

• identifying one or more standardized components for the sub-assembly of the medicament delivery device from a group of standardized components, wherein the group of standardized components comprises at least one of a group of interchangeable plunger rods, a group of interchangeable delivery member guards, and at least one of a group of interchangeable plunger rod springs and a group of interchangeable delivery member guard springs, wherein the plunger rods in the group of interchangeable plunger rods have a structural and/or dimensional difference relative to one another, wherein the delivery member guards in the group of interchangeable delivery member guards have a structural and/or dimensional difference relative to one another, and wherein the plunger rod springs comprise one or more distinct force values;
• identifying, based on the other standardized components identified, a force value for a plunger rod spring;
• including the plunger rod spring with the identified force value as one of the identified one or more standardized components;
• providing the identified one or more standardized components;
• providing a universal powerpack for the medicament delivery device;
• and
• assembling the sub-assembly of the medicament delivery device using the universal powerpack, and the identified one or more standardized components.