Soviet Nuclear Mortar
Self-propelled weapon “Condesator-2P” is a heavy system with mass of 64 tons, able to fire a 570 kg shell at the distance of 25,6 km. It was never serialy produced, only four units were made in total. It was first shown on Red Square of Moscow in 1957 and made a furore. Some foreign reporters supposed the machine was fake and was shown to create a threatening impression. But the system of 406 mm calibre was more than real.
The self-propelled gun was created in 1954, it was intended to destroy large military and industrial objects of an enemy at the distance over twenty five kilometres with practice and nuclear shells. Just in case there were created three types of super weapons: gun, mortar and recoiless weapon with the calibre much larger than ones of the American guns. In fact so large calibre appeared because Soviet nuclear engineers just could not create compact munition.
Horizontal aiming of the gun was performed by means of turning of all the tracked weapon, accurate aiming was carried out with help of a special electric motor through the steering drive. Vertical aiming was provided by the direct lift hoist. Shell weight was equal to 570 kg, maximum firing range – 25,6 km.
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We had nuclear shells deliverable by 155mm howitzers at roughly the same range when I was in an artillery battalion in the '80's. We used to joke that the only way we intended to fire them was while driving at top speed in the other direction on the autobahn. 
Craziest thing I heard of was from a good friend in the Special Forces. He was trained to carry nuclear mines in a backpack into the Fulda Gap... 
The NRA says these are just the thing for home defense: 
If our guys who fired a Davy Crocket were downwind they'd be suffering some very serious health consequences. Best be in a deep hole when the thing went off. Then run away.
The USA built 2,100 of these little nasties. 2,100 city destroyers. Think about it.
http://en.wikipedia.org/wiki/Davy_Crockett_%28nuclear_device%29
Most people don't realize the extent of our nuclear weapons program. They think the Trinity Test and the two bombs dropped on Japan were "one off" custom made weapons of mass destruction. But from its inception the Manhattan Project was built with the capacity to fight a full scale nuclear war with Germany and Japan, and later the Soviet Union. This capacity for mass producing these nuclear weapons was already set in place when Japan surrendered. Had Japan not surrendered we could have easily turned the entire nation into a nuclear wasteland.
If the Nazis had developed "The Bomb" we'd all be radioactive . Mutant armies would probably be fighting one another with pointed sticks and clubs. Fortunately for mankind it seems many European scientists looked at Germany going rotten and saw a bad moon rising. (If I ever see a mess of scientists leaving the USA, I will leave too, even if I have to walk across the desert with my family. Sailing away might work too.)
There was only a brief pause in U.S. atomic weapons production when World War II ended. They had to make the plants safer for Cold War use or they wouldn't get any workers. Americans were already a little suspicious of this radiation stuff. Thomas Edison himself had disavowed any further research into it after one of his colleagues, Clarence Madison Dally, was killed by x-rays. In 1903, a shaken Edison said "Don't talk to me about X-rays, I am afraid of them."
The Soviets, in post World War II catch up mode, were not so careful and made some bigger radioactive messes than we did. While we were throwing our radioactive waste into thin-walled steel tanks buried in the ground, the Soviets were dumping it into open trenches dug in the dirt. But it's not such a huge difference these days, now that our rotting steel tanks full of radioactive sludge are rusting away and leaking.
Here's a bigger U.S. gun we built so our soldiers could be a little further away from the blast:
My wife's dad saw a nuclear explosion up close, and marched across ground zero shortly afterwards. He was in a hole, butt up, head down, helmet on, arms shielding the back of his neck, eyes tightly closed, and he still saw the flash.
Later they took showers, scrubbing one another off until the Geiger counters said they were clean enough.
Their radioactive uniforms are buried out in the desert somewhere.
All these guys, and any civilians downwind, were essentially experimental animals.
Crazy.
