The German 31.5 inch railway gun, of which Dora was the second to be produced, were designed specifically to overcome major fortifications. When they were designed, the French Maginot Line was there intended target. The gun's armour piercing sheels could pierce up to seven metres of concrete before detonation whilst their High Explosive shells could create a crater 9m wide.

Neither the Dora nor its predecessor, the Schwerer Gustav, were ready by the time France fell. Instead, both guns were utilised in the east, the Schwerer Gustav during th siege of Sevastopol in the Ukraine and Dora during the Battle of Stalingrad.

The Gustav required its barrel to be replaced after the Siege of Sevastopol ended. By this opoint, it had fired almost 300 shells, 250 during testing and 48 during the siege. Dora Was never able to play a decisive role at Stalingrad, the Soviet counter attack threatened the gun's position and it was withdrawn.

Both guns were destroyed by the Germans to prevent their capture. The remains of Gustav were recovered by the Soviets whilst those of Dora were recovered by the US.