Once upon a time, in 1855, two independent American inventors named Azel S. Lyman and James R. Haskell began working together to develop a new type of multicharge cannon that Lyman had designed. The cannon used multiple charges spaced out along the length of the barrel. By 1885, Lyman and Haskell had secured Congressional funding, but their invention was rejected by the U.S. Army's Bureau of Ordnance. When Lyman's and Haskell's cannon was tested by the U.S. Army in the 1880's, enough propellant gases escaped around the side of the shell to frequently ignite the subsequent side charges too soon. Sixty years later, German engineers would refine the American invention to create the Vergeltungswaffe 3, or V-3.
In the 1930's, a handful of german engineers became enamored with the multicharge cannon concept. They understood that theoretically a multicharge cannon can fire a shell at a higher muzzle velocity with a lower peak pressure than can conventional cannon. With limited resources allocated by their superiors, they began constructing multicharge cannon, mostly in 20mm caliber. In 1943, at the urging of Albert Speer, Adolf Hitler ordered support for their work and the German government began construction of large scale guns. Much of the developmental work was conducted at Hillersleben Proving Ground in Germany and at Miedzyzdroje (a.k.a. Misdroy), Poland.
The German engineers were plagued with the same side-charge timing problems that were Lyman and Haskell. They tried electrical timing, but reverted to Lyman's and Haskell's approach of letting the gases behind the shell ignite the side charges.
V-3's were soon being constructed, the first at Mimoyeques, France. During this construction, French Resistance operators warned the Allies of the V-3, which the Germans had code-named, "Hockdruckpumpe". V-3's were the object of several bombing raids using 12,000 lbs "Tallboy" bombs. These raids failed to damage the V-3's until a lucky series of hits by Tallboys. So desperate were the Allies that B-17's were converted to remote control and packed with bombs for crashing into the V-3 bunkers. Two V-3's were used operationally, one in Belgium and the other in Luxembourg.
The V-3 might have been little more than a ballistic oddity were it not for the post-war activities. The V-3 was officially dismissed as an unworkable concept along with other German super gun experiments. Not one equation describing the V-3's operation was ever officially found. Coincidentally, the U.S., Canada and Great Britain made great strides in artillery development shortly after WWII, cuminating in nuclear cannon shells and projectiles fired into space from earthbound cannon.
Like the plot of an absurd science fiction movie or an episode of the TV show "Wild, Wild West", a mighty weapon was created in 1855 in a world of horse-drawn wagons and Kentucky rifles. Maybe truth really is stranger than fiction.