Lee-Enfield Mk .1 SMLE Mk. III (No.1 Mk.3) SMLE No.4 Mk.1 SMLE No.5 Jungle carbine
Caliber .303 British (7.7x56mm R)
Action manually operated, rotating bolt
Overall length 1260 mm 1132 mm 1129 mm 1003 mm
Barrel length 767 mm 640 mm 640 mm 478 mm
Weight 4.19 kg 3.96 kg 4.11 kg 3.24 kg
Magazine capacity 10 rounds in detachable box magazine

The Lee-Enfield series of rifles was born in 1895 as a marriage between the magazine and bolt action, designed by the J. P. Lee, and the new pattern of barrel rifling, designed at the Royal Small Arms Factory (RSAF) at Enfield. Originally known as Lee-Metford, this design was adopted by British army in 1888 and used a Metford pattern rifling with shallow groves, intended to be used with ammunition loaded with black powder. Introduction of the smokeless powders in the form of the Cordite showed that the Metford rifling was very short-living, so it was soon replaced with Enfield rifling, with 5 traditional land and grooves and left hand pitch. Early Lee-Enfield rifles, officially known as a ".303 caliber, Rifle, Magazine, Lee-Enfield", were carried by the British army through the Boer war (South Africa) of 1899-1902, and Boers, armed with their Mausers, taught to the Brit's some hard lessons. And, unlike some other Empires, Brit's were quick lo learn. In 1903, they introduced a new design, which improved over the older Lee-Metford's and Lee-Enfield's in some important respects. The main improvements was the introduction of the "universal" rifle idea. The common thinking of the period was to issue the long rifle for infantry and the carbine for cavalry, artillery and other such troops. The Brit's decided to replace this variety of sizes with one, "intermediate" size, that will fit all niches. This "one size fits all" rifle was called ".303 caliber, Rifle, Short, Magazine, Lee-Enfield, Mark 1", or, in short SMLE Mk.I, where "short" referred to the length of the rifle. This rifle passed some improvements during the following pre-WW1 years, finalizing in the 1907 as a SMLE Mk.III. Development and introduction into service of this rifle was accompanied with constant complaints of some "theorists", which stated that this rifle would be no good neither for infantry, nor for cavalry, so RSAF was set do design another rifle, patterned after the German Mauser, which also should be more suitable for mass production, than the SMLE. This rifle finally appeared in 1914 as an ".303 caliber Enfield Pattern 1914 rifle", or simply a P-14. With the outbreak of the Great war British troops were still armed with the "poor" SMLE Mk.III rifles, which soon turned far from any "poor", giving some hard time to the Germans. In fact, the SMLE Mk.III was a really good rifle, quite accurate, reliable and suitable for rapid and accurate firing. British soldiers were rigorously trained for both individual and volley fire marksmanship, and were routinely capable of firing 30 aimed shots per minute, which was quite a rate of fire for any non-automatic rifle. There were times when advancing Germans were impressed that they were under the machine gun fire, when Tommie used their salvo-firing techniques. During the war time the basic Mk.III design was slightly simplified to better suit the mass production needs, with omission of "volley" sights and magazine cutoffs, and with some production shortcuts. When the World War One was over, there were no questions of quality of basic SMLE design, but some improvements were suggested and introduced in later patterns, such as peep-hole, receiver mounted sights. These "inter war" patterns were not issued in any significant quantities until the 1941. In 1926, Britain's, quite confused with numerous 'Marks' and 'Marks with stars' of their weaponry, decided to adopt a new numbering system, so the SMLE Mark III became the "Rifle, No. 1 Mark 3". The "Rifle No.2" was a training version of the SMLE No.1 but chambered to .22LR ammunition. The "No.3" was assigned to the P-14 rifle, which was used in limited numbers. And the "Rifle No.4 Mark 1", widely known as a SMLE No.4 Mk.1, appeared in 1941. This was an improved and strengthened SMLE design, with heavier and stronger receiver, which also was faster and easier to machine, and with heavier barrel. The stock shape was shortened at the front part, giving away with the characteristic Mark III snub-nosed appearance. The barrel-mounted open rear sights were replaced with the receiver-mounted peep-hole sights, which were micrometer-adjustable. The latter feature was substituted by the simplified flip-up rear sights for wartime production, and this version became the No.4 Mk.1* rifle. By the end of the World War 2, when British and Commonwealth troops (also armed with SMLEs) started to fight in jungles of the South-East Asia, it was soon discovered that a "short" SMLE was still not short enough for the jungle combat, so a carbine version was adopted late in the 1944 in the form of the No.5 "jungle carbine". This gun was somewhat lighter and handier than No.4, but suffered from the "wandering zero" problems, which meant that the point of impact wandered during the time. The muzzle flash and recoil were also too strong, despite the flash-hider and rubber butt pad. The last, and by some opinions the finest "general issue" version of the SMLE was the No.4 Mk.2 rifle, which appeared in 1949. It was made by higher peacetime standards of fit and finish, than a wartime No.1 Mk.3s and No.4 Mk.1s, and served with British army until the mid-1950s, when the self-loading L1 SLR (semi-auto copy of the Belgian FN FAL) rifle in 7.62mm NATO was introduced into general service. But some SMLEs were left in military service, as a training, target and, especially, sniper rifles, known as Enfield L39 and L41, re chambered to the new standard 7.62mm NATO ammunition, and served well until the late 1980s, when there were replaced by the L96 sniper rifles. It should be noted, that SMLE rifles were produced and used not only in the UK. Australian, Canadian and Indian factories turned out more than million of the No.1 rifles with various improvements, which were used during both World wars and thereafter. During the WW2, Britain also acquired quantities of SMLE No.4 (marked No.4 Mk.1*) made under contract at the Savage Arms company in USA. In the 1950s, Indian Isaphore arsenal turned out some SMLEs re chambered to the 7.62mm NATO (.308 win) ammunition. These are distinguishable from .303 caliber rifles by the more squared outline of the magazine. Total numbers of all 'Marks' and 'Numbers' of the SMLE made during the 60 years in various countries is not less than 5 000 000 (yes, five millions) rifles.
The SMLE is a manually operated, rotating bolt action magazine fed rifle. The Lee-designed SMLE magazine is a first easily distinguishable feature. It holds 10 rounds of ammunition in staggered column form, and while the magazine itself is detachable, it is not intended to be reloaded when detached from rifle. Early Lee-Enfield's (Long Lee-Enfield's and SMLEs prior to Mark III) were loaded only by single rounds via the top receiver opening. Latter, the clip (charger) loading was introduced, and a rear receiver bridge with charger clip guides was added to the design. Some of the earlier marks were then retrofitted with charger loading ability during the 1907 - 1910. To load the magazine, one must use two standard 5-rounds clips. Loading by loose rounds was still available, but some care must be taken when loading cartridges into clips or in the magazine, due to the rimmed ammunition cases. Prior to the 1916, all SMLEs (and earlier Long Lee-Enfield's) were issued with so called "magazine cut-off" - a simple device, located at the right side of the receiver and intended to cut off the cartridge supply from magazine to the action when engaged, so rifle could be used as a single-loader, and ammunition in the magazine could be saved for the hottest moments of combat. This was an outdated idea even when it was first introduced, so it was easily discarded when the need to speed up production arose. The magazine itself should be detached only for cleaning, maintenance and repair, and every rifle was issued with only one magazine. The magazine catch is located inside the trigger guard.
The bolt action, another invention of the James Paris Lee (along with magazine), is the other most famous feature of the SMLE. The rotating bolt has two lugs that lock into the receiver walls at the rear part of the bolt, thus saving some part of the bolt length and bolt pull, when comparing to the forward lugs locking. This shorter bolt pull, along with charging handle, located at the rear part of the bolt and bent down, lent itself to quick reloading. Add a relatively high capacity magazine with fast clip reloading and here you have one of the fastest practical rates of fire along with contemporary designs. The SMLE was a striker fired gun, with cocking on the bolt close action and a dual-stage trigger. The bolt head with the extractor was a separate, non-rotating unit, screwed into the bolt body. The safety was located at the rear left side of the receiver and was easily operated by the firing hands' thumb finger. One notable feature of the Lee bolt action was that the bolts were not interchangeable between different rifles of the same mark Each bolt must have been fitted to its respective action, thus making the production and in-field bolt replacement more complicated. The insufficient head space problem on the pre-No.4 SMLEs was solved my manual sandpapering the respective bolt-head, and since the No.4 rifle, there were 4 standard sizes of the bolt heads, from which armour er could select one, most suitable for the particular action.
The sights of the Mark III / No.1 Mk.3 SMLEs were a combination of the barleycorn front (an inverted V-shape) and V-notch adjustable rear sights, mounted on the barrel. The front sights were protected by the two "ears" on the stock nose-cap. Latter the front sight were changed to post type, and the rear - to the U-notch type, and since the introduction of the No.4 rifle the barrel-mounted open rear sight was replaced with peep-hole one, mounted on the receiver, which made the sighting line much longer and improved the long-range accuracy. Sniper No.4 Mk.1(T) rifles, made during the WW2, were equipped with detachable optical scope mounts at the left side of the receiver. The scope was carried in the separate box when not in use. No.4 Mk1* rifles, made during the WW2, were equipped with the simplified, two position aperture (peep-hole) sights, marked for 300 and 600 yards ranges only. Pre-1916 Lee-Enfield's were also equipped with interesting device, called the "volley" sights. This device was mounted at the left side of the stock, ahead of the magazine, and was used to provide an indirect fire capability at the ranges from 2 000 and up to outstanding 3 900 yards (1800 - 3550 meters). While the individual marksmanship at such ranges with rifle was a nonsense, the salvo firing by large squads at the distant and large targets (such as tight infantry or cavalry formations) can do some damage to the enemy. This was, obviously, an idea of the pre - machine gun and pre - light artillery period, and it was happily dropped during the WW1.
The famous by its distinguishable shape stock of the SMLE featured a semi-pistol grip, a steel butt plate with a trapdoor and a compartment in the butt for tools and cleaning equipment. The "flat-nosed" for end covered the barrel up to the muzzle, and has a small stud, protruding forward under the muzzle for bayonet mounting. Most SMLEs have a small brass disc inset into the right side of the butt, which was used for regimental markings (unlike the German Mausers, where the similar steel disc was used as a bolt unit disassembly tool). The conventional sling swivels were mounted on the frond hand guard band and under the butt. Mk.4 No1.(T) sniper rifles also featured an additional wooden cheek rest on the top of the butt for more comfortable sighting while using the scope.
In general the SMLE were ones of the best bolt action battle rifles, fast-firing, powerful and reliable. While being less suitable for "sporterizing" than Mausers, they are still popular among civilians as a hunting and plinking weapons, and also as a part of the history. The key deficiencies of the SMLE were probably the rimmed ammunition and non-interchangeability of bolts, but the advantages of this design were mush bigger and Lee-Enfield's in all its guises served the Britain and the British Commonwealth for more than 60 years in the front line service and much longer as a specialized weapon (training and sniper).

**Data resource http://world.guns.ru/rifle/rfl04-e.htm