J.R. · Revolver
Cooper Underhammer Pepperbox
Double action · .36 Caliber Percussion (Cap and Ball) · introduced 1843
Also known as J.R. Cooper Patent Pepperbox, Cooper Patent Under-Hammer Pepperbox Revolver, Cooper Ring-Trigger Pepperbox
About the Cooper Underhammer Pepperbox
The Cooper Underhammer Pepperbox is a mid-19th-century British percussion cap-and-ball revolver patented by John Rock Cooper of Birmingham in 1843. Its six barrels are bored from a single solid steel cylinder that revolves as a unit, and it is fired by an unusual underhammer mechanism whose percussion nipples sit beneath the barrel cluster and are struck from below. A ring trigger operating the self-cocking double-action lock advances the barrels and releases the hammer in a single pull. Typically chambered around .36 caliber, it was a popular personal-defense sidearm sold on the British civilian market until roughly the mid-1850s.
John Rock Cooper's 1843 patent placed the hammer beneath the barrel cluster, a layout that kept the lock out of the shooter's line of sight and gave the compact pepperbox an unusually clean, hammerless profile for a percussion revolver of its day.
Cooper Underhammer Pepperbox specifications
General
- Type
- Revolver
- Action
- Double action
- Firing mechanism
- Percussion
- Trigger
- Double action
- Calibres
- .36 Caliber Percussion (Cap and Ball)
- Magazine capacity
- 6 rounds
- Magazine
- Internal
Dimensions
- Barrel length
- 89 mm (3.5 in)
- Overall length
- 197 mm (7.8 in)
- Weight (empty)
- 0.62 kg (1.37 lb)
Barrel
- Rifling
- None
Materials
- Barrel
- Steel
- Receiver / frame
- German silver
- Stock
- Walnut
- Finish
- blued
Performance
- Muzzle velocity (typical)
- 229 m/s (751 fps)
- Effective range
- 10 m
History
- Introduced
- 1843
- Discontinued
- 1853
- Production status
- Discontinued
- Country of origin
- GB
- Designer
- John Rock Cooper
Features
- Underhammer mechanism
- Ring trigger
- Self cocking double action
- Six barrel revolving cluster
- Nickel silver frame
Bore diameters vary between surviving examples, quoted in the period British system as roughly 80-bore to 60-bore (about .36 to .40 caliber). Higher-grade examples used a solid nickel-silver (German silver) frame rather than plated brass, with walnut grip scales.
