
The origins of the modern British military rifle are within its predecessor the Brown Bess musket. While a musket was largely inaccurate over 80 yards, due to a lack of rifling and a generous tolerance to allow for muzzle-loading, it was cheaper to produce and could be loaded quickly. The use in volley or in mass firing by troops meant that rate of fire took precedence over accuracy. A similar tactical preference would be a factor in considerations regarding rifle design in the late 19th century to early 20th century, when rate of fire would be a key design consideration for British bolt-action rifles. Beginning in the late 1830s, the superior characteristics of the new rifles caused the British military to phase out the venerable .75 calibre Brown Bess musket in favour of muzzle-loading rifles in smaller calibres. Early rifles were non-standard and frequently used adaptations from components of the Brown Bess, including locks and stocks adapted to new rifled barrels. It was not until the late 19th century that the rifle fully supplanted the musket as the primary weapon of the infantryman.
NOTE: Since I personally am not interested in the time when the British forces used muskets, I won’t start the Martini-Henry Mk IV rifle here

The Martini–Henry rifle was adopted in 1871, featuring a tilting-block single-shot breech-loading action, actuated by a lever beneath the wrist of the buttstock. The Martini–Henry evolved as the standard service rifle for almost 20 years, with variants including carbines.
Unlike the Snider it replaced, the Martini–Henry was designed from the ground up as a breech-loadingmetallic cartridge firearm. This robust weapon uses a tilting-block, with a self-cocking, lever operated, single-shot action designed by a Swiss, Friedrich von Martini, as modified from the Peabody design. The rifling system was designed by Scotsman, Alexander Henry.
The Mark I was adopted for service in 1871. There were three further main variations of the Martini–Henry rifle, the Marks II, III and IV, with sub variations of these called patterns. In 1877, a carbine version entered service with five main variations including cavalry and artillery versions. Initially, Martinis used the short chamber Boxer-Henry .45 calibre black powder cartridge made of a thin sheet of brass rolled around a mandrel, which was then soldered to an iron base. Later, the rolled brass case was replaced by a solid brass version which remedied a myriad of problems.
Martini–Metford and Martini–Enfield
Martini–Enfield rifles were mostly conversions of the Zulu War era .450/577 Martini–Henry, rechambered to the .303 British calibre, although a number were newly manufactured. Early Martini–Henry conversions, began in 1889, using Metford rifled barrels (Martini–Metford rifles), which were more than suitable for the first black powder .303 cartridges, but they wore out very quickly when fired with the more powerful smokeless ammunition introduced in 1895, so that year the Enfield rifled barrel was introduced, which was suitable for smokeless ammunition. The Martini–Enfield was in service from 1895 to 1918 (Lawrence of Arabia’s Arab Irregulars were known to have used them during the Arab Revolt of 1916–1918), and it remained a reserve arm in places like India and New Zealand well into World War II.

The first British repeating rifle incorporated a bolt–action and a box-magazine; this was developed through trials beginning in 1879, and adopted as the Magazine Rifle Mark I in 1888. This rifle is commonly referred to as the Lee–Metford or MLM (Magazine Lee–Metford).
The “Lee” comes from James Paris Lee (1831–1904), a Scottish-born Canadian-American inventor who designed an easy-to-operate turnbolt and a high-capacity box magazine to work with it. The box magazine, either Lee or Mannlicher designed, proved superior in combat to the Kropatschek-style tube magazine used by the French in their Lebel rifle, or the Krag–Jørgensen rotary magazine used in the first US bolt-action rifle (M1892). The initial Lee magazine was a straight stack, eight-round box, which was superseded by the staggered, ten-round box in later versions, in each case more than were accommodated by Mannlicher box magazine designs. The “Metford” comes from William Ellis Metford (1824–1899), an English engineer who was instrumental in perfecting the .303 calibre jacketed bullet and rifling to accommodate the smaller diameter.
During the development of the Lee–Metford, smokeless powder was invented. The French and Germans were already implementing their second-generation bolt-action rifles, the 8 mm Lebel in 1886 and 7.92 mm Gewehr 88 in 1888 respectively, using smokeless powder to propel smaller diameter bullets. The British followed the trend of using smaller diameter bullets, but the Lee–Metford design process overlapped the invention of smokeless powder, and was not adapted for its use. However, in 1895, the design was modified to work with smokeless powder resulting in the Lee–Enfield.
A contrast between this design and other successful bolt actions of the time, such as the Mausers and US Springfield, is the rear locking lug. This puts the lug close to the bolt handle, where the pressure is applied by the operator; in essence the force is close to the fulcrum point. Without great explanation, this results in an easier and swifter operation versus the Mauser design, resulting in a greater rate of fire. However, the sacrifice is strength as the fulcrum point has moved away from the force of the explosion, thus making the length of the bolt a lever working against the holding power of the rear lug. This was a limiting factor in the ballisticscapacity of this design.
Another difference between the Lee and the Mauser designs was the use of “cock-on-closing”, which also helped to speed cycling by making the initial opening of the breech very easy. The closing stroke, which is generally more forceful than the opening stroke, cocks the rifle, adding to the ease of use. The Lee design also featured a shorter bolt travel and a 60-degree rotation of the bolt; these attributes also led to faster cycle times.
Over the service life of the design, proponents and opponents would stress rate-of-fire versus ballistics respectively. The basic Lee design with some tinkering was the basis for most British front-line rifles until after World War II.