A finger grip for a flangeless container, the finger grip having a skirt removably attachable to an open end portion of the container and a lip that extends radially outwardly from the skirt. The flangeless container is fillable by capping the container using a cap element to attach the finger grip to the container; installing the container in a container support assembly including a tray having a plurality of wells; filling the container; inserting a piston into the container; and removing the finger grip. Each well has a depth less than a predetermined length of the container, a lower portion of each well having a first cross-sectional shape similar to but greater than the cross-sectional shape of the flangeless container, an upper portion of each well having a second cross-sectional shape similar to but greater than the first cross-sectional shape.