When I've shot Lee Enfields in a timed stage i loaded my chargers so each successive cartridge's rim was in front of the rim of the cartridge below. In order to avoid inserting the charger upside down I painted one half of my chargers bright yellow. As long as the yellow half was up I was good to go. I wanted to see how the good ol' Lee Enfield would fare against AR15s with all the bell's and whistles so I entered several IPSC competitions with both a SMLE and a No.5. I actually beat some ARs in a few matches but I was never in the money.
When the chargers are loaded the proper way it makes no difference which way is up.
Imagine what the soldiers in the trenches would do if they had to paint their ammo chargers.