what is the absolute upper bound on the size of gunpowder cannons, (not rail guns or similar) in terms of shell weight and bore diameter before some mechanical or material problem prevents it from being usable?


  1. Assume today's technology.
  2. The projectile should be a metal ball
  3. The gunpowder should be fed loose, not in a cartridge.
  4. The cannon should be able to be used more than once without destroying itself.
  5. The cannon should have a range greater than 2km

I'm specifically looking for the limit of the materials that contain the explosion.

For example: The metals will crack if more than "X" kg of gunpowder explodes inside, or the firing mechanism will be too damaged in the explosion for the cannon to be reused.

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    $\begingroup$ Welcome to Stack Exchange! - What technology level are we talking? Are these old-fashioned fuse-lit cannons? Are they made by casting or boring? Are they made from iron or steel? Would a Big Bertha be an acceptable answer? en.wikipedia.org/wiki/Big_Bertha_(howitzer) $\endgroup$ – chasly from UK Dec 12 '18 at 23:08
  • $\begingroup$ What do you mean by mechanical problem? Like getting the Shell into the cannon? moving the cannon? or damage to the cannon when firing it? $\endgroup$ – Shadowzee Dec 12 '18 at 23:11
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    $\begingroup$ There is a list of the largest cannon on Wikipedia, organized by the kind of cannon (stone ball, iron ball and shot, explosive shell). $\endgroup$ – AlexP Dec 13 '18 at 0:46
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    $\begingroup$ The cost and awkwardness goes up a lot faster than the boom, there's a point where nobody is going to bother but there's no maximum size. (There is a maximum velocity, though--the shell always is thrown slower than the burn speed of the propellant.) $\endgroup$ – Loren Pechtel Dec 13 '18 at 6:19
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    $\begingroup$ The Krupp K5 railway cannon was capable of firing normal shells 30km, and a special version which was bored out to fire the Peenemünde Arrow Shell an astounding 100km. Gerald Bull was a Canadian artillery scientist who hoped to put a shell into orbit, and HARP test guns were throwing shells to a maximum altitude of 180km. Sadly, he started working for unsavoury charters and was assassinated. $\endgroup$ – Thucydides Dec 14 '18 at 3:36