A modular barrel and screw assembly for use in injection molding including a barrel having a barrel body, a separate barrel injection portion and a separate barrel end cap, with the barrel end cap being removably connected to the barrel injection portion and the barrel injection portion being removably connected to the barrel body, and a screw assembly having a screw tip assembly removably connected to a screw portion, wherein an injection chamber having a shot volume is defined by the barrel injection portion, the barrel end cap and the screw tip assembly. The modular barrel and screw assembly enables servicing of the barrel injection portion, barrel end cap and/or screw tip assembly without requiring removal of the barrel body, and enables use of a plurality of alternative corresponding separate barrel injection portions, separate barrel end caps and tip assemblies that provide a plurality of different shot volumes.