The Mars Automatic Pistol, also sometimes known as the Webley-Mars, was a semi-automatic pistol developed in 1900 by the Englishman

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 Hugh Gabbet-Fairfax and distributed by the Mars Automatic Pistol Syndicate Ltd. of Birmingham. It was manufactured first by Webley & Scott

Webley and Scott

Webley & Scott is an arms manufacturer based in Birmingham, England. Webley produced handguns and long guns from 1834 to 1979, when the company ceased to manufacture firearms and instead focused on producing air pistols and air rifles...

 and later by small gunmakers in Birmingham and London. Manufacture ceased in 1907.

The Mars Automatic Pistol is noted for being available in a variety of 8.5 mm, 9 mm and .45 calibres. These were all bottlenecked cartridge

Cartridge (firearms)

A cartridge, also called a round, packages the bullet, gunpowder and primer into a single metallic case precisely made to fit the firing chamber of a firearm. The primer is a small charge of impact-sensitive chemical that may be located at the center of the case head or at its rim . Electrically...

s with a heavy powder loading, making the .45 version the most powerful handgun in the world for a time. It used a unique long recoil rotating bolt action which ejected spent cartridges straight to the rear.

The Mars Automatic Pistol was rejected by the British War Office

War Office

The War Office was a department of the British Government, responsible for the administration of the British Army between the 17th century and 1964, when its functions were transferred to the Ministry of Defence...

 as a possible replacement for the Webley & Scott Revolver

Webley Revolver

The Webley Revolver was, in various marks, the standard issue service pistol for the armed forces of the United Kingdom, the British Empire, and the Commonwealths from 1887 until 1963.The Webley is a top-break revolver with automatic extraction...

, then in service with the British Army

British Army

The British Army is the land warfare branch of Her Majesty's Armed Forces in the United Kingdom. It came into being with the unification of the Kingdom of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army incorporated Regiments that had already existed in England...

, because of the unacceptably large recoil, considerable muzzle flash, and mechanical complexity. The captain in charge of tests of the Mars at the Naval Gunnery School in 1902 observed, "No one who fired once with the pistol wished to shoot it again". Shooting the Mars pistol was described as "singularly unpleasant and alarming". It has since become a collectors' item because of its rarity and as an example of the earliest developments in semi-automatic pistols. It inspired the design of the present day Desert Eagle

Desert Eagle

The Desert Eagle is a large-framed gas-operated semi-automatic pistol designed by Magnum Research in the U.S. and by IMI in Israel; the pistol is manufactured primarily in Israel by IMI...

.