The Mossberg Brownie was a four-barreled, .22 Long Rifle

.22 Long Rifle

The .22 Long Rifle rimfire cartridge is a long established variety of ammunition, and in terms of units sold is still by far the most common in the world today. The cartridge is often referred to simply as .22 LR and various rifles, pistols, revolvers, and even some smoothbore shotguns have...

 pistol

Pistol

When distinguished as a subset of handguns, a pistol is a handgun with a chamber that is integral with the barrel, as opposed to a revolver, wherein the chamber is separate from the barrel as a revolving cylinder. Typically, pistols have an effective range of about 100 feet.-History:The pistol...

, similar to a derringer

COP 357 Derringer

The COP 357 is a 4 shot Derringer type pistol chambered for the powerful .357 Magnum round. It was designed by Robert Hillberg, based on his earlier work on the Hillberg Insurgency Weapon.It was manufactured by the now defunct COP Inc...

 or pepperbox, produced by O.F. Mossberg & Sons

O.F. Mossberg & Sons

O.F. Mossberg & Sons is an American firearms manufacturer, specializing in shotguns, rifles, scopes and firearm accessories. From the 1940s through the 1960s, it also produced a line of .22 caliber target and sporting rifles....

 from 1920-1932. The Brownie was based on an earlier pistol patented and licensed to the Shattuck Company by Oscar Mossberg.

Design

The pistol has a double-action trigger and a rotating firing pin. Each pull of the trigger cocks and releases the hammer as well as rotating the firing pin to fire each chamber in succession. A top-mounted latch released the barrel assembly to open forward. Mossberg provided a piece of bent sheet metal to extract spent casings.

From 1986-1987 Advantage Arms produced pistols with many features of the Brownie. The Advantage Arms design was also produced in a .22 Winchester Magnum Rimfire chambering and models featured an internal extractor.

Cobray also produced an odd revolver called the "Pocket Pal

Cobray Pocket Pal

The Cobray Pocket Pal was a unique revolver that featured the same break-action, layout, and hammer system of the Mossberg Brownie. Cobray combined this with a unique twin-barrel, dual-caliber system. Two "zig-zag" revolving cylinders were provided, one in .22 LR and the other in .380 ACP...

" that featured the same break-action, layout, and hammer system of the Brownie. Cobray combined this with a unique twin-barrel, dual-caliber system. Two "zig-zag" revolving cylinders were provided, one in .22 LR and the other in .380 ACP

.380 ACP

The .380 ACP pistol cartridge is a rimless, straight-walled pistol cartridge developed by firearms designer John Browning. The cartridge headspaces on the mouth of the case. It was introduced in 1908 by Colt, and has been a popular self-defense cartridge ever since...

. The same hammer fired either the .22 caliber in the bottom barrel or the .380 in the top depending on which cylinder was installed.