a bottom-front pivot. After loading, the assembly is tilted back into firing position and locked closed. Webley went on to produce more revolvers for the civilian market. Webley's popular pocket revolver, The British Bull Dog, was developed in 1872, available in .44 Short Rimfire, .442 and .450 calibers, and widely exported and copied. Smaller scale versions in .320 and .380 calibers were added later. Although often attributed to Webley, Webley only produced some of the revolvers now commonly referred to as Webley .577 Boxer Revolvers, which used the most powerful handgun cartridge of the day, the .577 Boxer. It was produced by Webley under licence from the firm of William Tranter of Birmingham, whose design it actually was. Webley was just one of several firms licensed to use Tranter's double-action lock and particularly Tranter's patented revolving recoil shield, which was a key feature of the early .577 calibre revolvers. In 1879 Webley developed & sold commercially a rugged and powerful revolver intended for the British military, the WG or Webley Government in .455/.476, the WG's cylinder was long enough for .44 Russian & .45 Colt length rounds [Jim Farmer has seen .45 Colt chambered WG models, but is unsure if they were converted .455s- further research is needed for WG chamberings- he has seen Belgian WG copies made in .44-40]. The WG frame & cylinder were then shortened for the .455 & the variant was adopted in the 1880s as the Webley Mk 1. Nicknamed "the British Peacemaker" in the United States, the Mk 1 was manufactured in .450, .455 Webley, and .476 calibre and founded a family of revolvers that were the standard handguns of the British Army, Royal Navy, and British police constabularies from 1887 to 1918. The Mark VI (known as the Webley Revolver No. 1 Mark VI after 1927) was the last standard service pistol made by Webley; the most widely produced of their revolvers, 300,000 were made for service during World War I. Webley began experimenting with semi-automatic action in 1900 and in 1909 they began producing a series of semi-automatic pistols for civilian and police use. Their .32 Automatic Pistol was adopted by London's Metropolitan Police in 1911. The same weapon in .38 calibre was used by the Royal Navy as a substitute standard weapon during World War II. The Ordnance Factory Board of India still manufactures .380 Revolver Mk IIz cartridges, as well