A long firearm with four barrels (typically two shotgun barrels and two rifle barrels).
2018, James Ballou, Arming for the Apocalypse: Assembling Your Survival Arsenal ... While You Still Can, Prepper Press
[…] three-barreled drillings, the two-barreled shotgun/rifle cape guns, and the four-barreled vierlings, which all featured some combination of rifle with shotgun barrels within the same gun.
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