gunpowder tea, n. — Green’s Dictionary of Slang

gunpowder tea n.

[note British Army sl. gunfire, an early morning cup of tea served out to troops before going on first parade]

(US) gunfire.

1865

M.L. Byrn Adventures of Fudge Fumble 51: The great American hero, ‘Old Hickory,’ was giving the British gunpowder-tea in real ‘Yankee style.’.