Seeing as this thread kinda' died.....
Today is the 53rd anniversary of operation 'Upshot-Knothole Grable', the one and only test of an artillery launched 'atomic' (or fission) shell. And it was successful, depending on your definition of success, meaning that they did indeed launch and detonate a fission weapon from a piece of towed artillery: specifically, a 280mm howitzer specifically built for this purpose and nicknamed 'Atomic Annie'. Part of that nickname comes from the artillery's original source, a 240mm rail gun designed, built and used by the Germans in WWII, two of which were used to devastating effect during the allied invasion of Anzio and given the nickname 'Anzio Annie' and 'the Anzio Express' but also called 'Robert' and 'Leopold' by their German users.
This was also a somewhat unusual fission device as it was a 'cannon' type weapon rather than an implosion weapon; only four cannon type fission weapons have ever been tested or used: Little Boy, dropped on Hiroshima, this specific artillery shell and two more W33 artillery shells although neither one was actually fired from a piece of artillery but rather detonated as a static, or 'in- place' test.
Of course this all took place during the time when it was still though nuclear arms could be used in an actual war that would be considered 'winnable'. Later on, nuclear devices got so big that the new philosophy M.A.D (mutuality assured destruction- meaning all combatants and likely everyone else would simply lose and there was no possibility of a winner).
So here is to clever American engineers and scientists..... they actually made this thing work. I do not know if it had any particular use but it may have been a viable deterrent in a close- order battle between the eastern and western forces in Europe. ?? No matter, it was still quite the feat to get a fission weapon to withstand the fantastic forces of an actual artillery piece launch and then still detonate and function afterward.
Brian