Forgotten History: World's Biggest Black Powder Cannon

The 100-ton Armstrong gun in Malta's Fort Rinella is the largest black powder cannon ever built.

The largest muzzleloading black powder cannons ever built were the Armstrong 100-ton guns which saw service with the Italian Navy and with British coastal fortifications on Malta and Gibraltar. They were purchased by the Italians first, to outfit a pair of new super battleships, each vessel having two turrets with two of these guns in each. To avoid being outclassed, the British ordered two guns for installation to protect the Grand Harbor of Malta and two more to protect Gibraltar. Today one survives at each location, and we are visiting the Rinella Battery in Malta, which was built to house one of the Maltese guns.

These guns had a maximum range of 8 miles, and was capable of piercing 15 inches of iron armor at 3 miles. It had a 17.7 inch (45cm) bore fired a 2000 pound (900 kg) shell with a 450 pound (200kg) charge of black powder. The gun itself weighed approximately 102 tons, and with its cradle and a shell the whole assembly came in at 150 tons.

Aside from the massive scale of the piece, the most interesting part of its design is actually the loading machinery. Because of the titanic size of the gun and ammunition, Armstrong designed a fascinating hydraulic reloading facility which makes up the body of the fortress in which the gun is set. A pair of steam engines drove a pair of hydraulic accumulators, which provided hydraulic pressure to move the gun on its carriage, to douse the barrel after firing, to hoist ammunition into position for loading and power a 60-foot (18m) ramrod to mechanically ram the charge and shell into place. Two mirror-image reloading galleries under the fortification operated in turn, giving the gun a sustained rate of fire of 1 round every 6 minutes - at least until its 120-round barrel life was exhausted.

I am grateful for the Malta Tourism Authority's assistance in helping to make this visit and video possible, and would also like to give special thanks to Simon, our awesome reenactor guide!