I broke it up with my fingers filled a quarter of the tube up lightly packed it down untill it was full.
Envision being a butane molecule looking for the easiest way through a packed column, and how a loose pack would look like a winding obstacle course, and a packed column would look like a filter.
We get the best yield reducing 15% moisture content material to 10 mesh and packing to a density of 4.2 grams per cubic inch. Any dead space is packed with coffee filters.
We break up lightly by hand for bragging rights extracts, to minimize the number of ruptured leaf cell walls exposed to the solvent, but still pack it firmly. Packing regularly during the process of filling the tube, as opposed to filling and then trying to pack it down evenly.
I push hard until movement ceases, but don't push any harder than that, or hammer, and use a dowel close to the diameter of tube, which shouldn't be larger than about one inch ID, for best efficiency.
The way to tell how well you are doing, is by microscopic examination of the spent material, to look for intact resin heads. The stalks will remain behind, but the bulbous heads should all/mostly be gone.
If not, repack and rerun.