An ammo locker was essentially an ammunition box bolted onto the back of the turret. The addition of ammo lockers allowed for much larger stores of machine gun and main gun ammunition, increasing the tank's overall potency.

The added storage space also increased the amount of special ammunition that could be stored, such as smoke rounds and flares. Thus, the addition of ammunition lockers increased not only the tank's potency, but also its versatility.

Both Germany and the Soviet Union fitted some variants of their tanks with ammunition lockers. Yet while only the KV series of Soviet tanks truly employed an ammo locker, ammo lockers became a common feature on many German tank variants.

WHERE TO LOOK FOR AN AMMO LOCKER -

Look at the rear of the turret and try to spot a protruding container. On German tanks, the rear face of the ammo locker tends to be curved.