The COP (Compact Off-duty Police) derringer was a four-shot 357 Mag over-under two-by-two design — four barrels in a 2x2 stack. Made by COP Inc. and distributed by American Derringer. Doubled the typical derringer capacity. Type: Derringer Action: Break-Action Caliber: 357 Mag Capacity: 4 Year introduced: 1983, USA Weight: 28 oz Overall length: 5.5" Status: Discontinued Intended use: concealed carry, law enforcement backup