A chromatography cartridge with a packed bed is manufactured from an inner and outer chamber, the inner chamber being in an insert that is slidable into the outer chamber with openings in each such that a slurry that is originally placed in the interior of the outer chamber flows into the inner chamber as the parts are being pressed into each other. During the assembly, the particles in the slurry are compressed to fill the smaller volume of the inner chamber and excess liquid is discharged through ports in both chambers. The construction allows for a highly precise and reproducible column filling process with a minimum of steps and operator intervention and thereby low cost and reduced error.