Flange measurements of LTO cartridge reels from several manufacturers with different packing conditions are presented. More specifically, the axial flange deflections are recorded with and without tape at four radial locations on both top and bottom flanges. This work introduces a novel means of characterizing flange deflection by measuring the outer surface of the flanges. By subtracting out the flange height with no tape, the change in flange taper with packing can be observed. Tape tension, number of wraps, and packing propensity are studied across three cartridge types. Taper changes of up to 160 m are observed. An axisymmetric finite element model is developed to explain the observed deflections.