Gerald Bull's Super Cannons...

[Panther Al]

These two guns are the very definition of immobile: the "small" test cannon was installed into a pit to support a barrel somewhere around 100'.

For the Size of the guns they was accurate enough: in essence, you got to pick a few hundred yard circle where the odds was fifty percent the round would land in it. And since the gun was mounted in a circular pit, it could be aimed at Isreal as well as Iran. Isreal saw it as a threat because Saddam was eager to develop a chemical round for it. They wasn't too worried about nukes: they already zapped Saddams nuke program, and if they tried to restart it they would do so again.