The Zig-Zag was a single action revolver

Revolver

A revolver is a repeating firearm that has a cylinder containing multiple chambers and at least one barrel for firing. The first revolver ever made was built by Elisha Collier in 1818. The percussion cap revolver was invented by Samuel Colt in 1836. This weapon became known as the Colt Paterson...

 manufactured by Mauser

Mauser

Mauser was a German arms manufacturer of a line of bolt-action rifles and pistols from the 1870s to 1995. Mauser designs were built for the German armed forces...

 during the late 19th century. It is chambered in a 6mm calibre round and is fed from a 6 round grooved drum hence the name of the revolver.

The original Zig-zag revolver had a solid frame and loading gate. It was invented in 1878 and was the first German military handgun to fire modern brass cartridges. It replaced the earlier needle-fire and pinfire

Pinfire

A pinfire firearm cartridge is an obsolete type of brass cartridge in which the priming compound is ignited by striking a small pin which protrudes radially from just above the base of the cartridge....

 revolvers.

In 1886 an improved 9mm version with a hinged frame was introduced

In 1896 the Zig-Zag was replaced by the semi-automatic Broomhandle Mauser, but many of the older revolvers remained in use until after World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

.