Culverin properly means a serpent (Latin, colubrinus, the coluber), but is applied to a long, slender piece
of artillery employed in the sixteenth century to carry balls to a great distance. Queen Elizabeth's “Pocket
Pistol” in Dover Castle is a culverin.

I had a Tory ancestor who made them, but sold them to the British, and had to flee to Halifax and thence to England. When I was a boy, "Go to Halifax!" was a permissible euphemism for "go to Hell".