was adopted in 1916 as the Short Magazine Lee-Enfield (SMLE) No. 1 Mark III.
The Rifles
The No. 5 Mark I carbine weighs about 8.9 pounds, has a 25.2” barrel and is 44.8” overall. It has a full length forend, and the rear sight is mounted on the barrel.
The No. 4 Mark I rifle, about 8.6 pounds, has a 25.2” barrel and is 44.4” overall. Its forend extends nearly to the muzzle, and the rear sight is mounted on the receiver bridge. It was adopted in 1941.
The No. 5 Mark I carbine weighs about 7.2 pounds, has a 20.5” barrel and is 39.1” overall. Often called the “Jungle Carbine,” it has a short sporter-type forend and a funnel-like flash hider on the muzzle, but is otherwise like the No. 4 rifle. It was introduced in 1944. All Lee-Enfields were discontinued in 1954.
The No. 1 Mk. III Action
The Lee-Enfield receiver (called the “body” in England) is a one-piece steel forging which required a great many machine operations before it was finished. It is more complex than the usual centerfire turnbolt action because of the two-piece stock design; the separate buttstock is attached to the rear of the receiver (called the “butt socket”) by a through-bolt. The receiver forging was made with a large mass of metal on its rear which was milled and threaded to accept the buttstock tenon and the through-bolt. This is a very secure and rugged stock fastening.
The front end of the receiver has right-hand threads of the common V-type. A heavy collar is left inside the rear of the receiver ring against which the flat breech end of the barrel butts. The barrel is also made with a reinforced shoulder which butts against the front of the receiver, making a rigid barrel-to-receiver joint. A slot cut through the right side of the collar (and a matching beveled notch in the breech face of the barrel) admits the extractor hook. The collar closely surrounds the front of the bolt head and provides a good seal at the breech. Neither the face of the barrel (chamber) nor the bolt head is recessed for the cartridge head. Since the cartridge rim is nearly the same diameter as the bolt head, the head is so well sealed that a recess is not needed.
The center of the receiver is bored and milled to accept the two-piece bolt. The receiver bridge is slotted to allow passage of the right locking lug/guide rib and the extractor lug on the bolt head.
The heavy left wall of the receiver is slightly lower than the top of the receiver ring line. A shallow thumb notch is cut into it to aid in loading the rifle from the top through the opened action. The right wall is milled much lower than the left, providing ample opening for loading and ejection.
The receiver bridge is slotted through. It is, however, bridged over by the narrow clip-charger guide bridge over the middle of the receiver, connecting the high left wall with the low right wall. It appears that this clip-charger bridge was made from a separate piece of metal, then afterward forged to become integral with the receiver. The top front of this bridge is grooved to accept the 303 British stripper clip.
The two-piece bolt has a separate bolt head threaded into the front of the bolt body. The small hooked extractor fits in a slot through a lug on the bolt head, and is held in place by, and pivots on, a screw through the underside of the lug. A small but sturdy flat V-spring tensions the extractor. The extractor easily snaps over the rim of a cartridge placed in the chamber.
The bolt has dual-opposed locking lugs located slightly to the rear of its center. The left (bottom) locking lug engages in a recess milled into the left wall of the receiver bridge. The long guide rib on the right (top) of the bolt is also the right locking lug—it engages forward of the receiver bridge wall, on the right. Both lugs are solid, and the rear locking surface of each is slightly angled to cam the bolt forward as it rotates to the fully locked position. In addition, the front surface of the left lug is also angled to match the surface in its locking recess. This provides the initial extraction power when the bolt handle is raised. The bolt handle, at the extreme rear end of the bolt, has a tapered square-to-round stem that ends in a round grasping ball. When the bolt is closed and locked, the bolt handle lies against the butt socket of the receiver, with the grasping ball only slightly away from the side of the rifle. There is no auxiliary locking lug on the bolt.
The bolt head does not turn with the bolt. As the bolt is fully closed, the threads of the bolt head draw it against the front of the bolt—so the thrust of firing is not placed on the threads. The large lug on the bolt head housing the extractor also acts as the bolt-stop when it contacts the receiver bridge wall as the bolt is opened. A lip under the outside edge of the extractor lug fits over a groove cut into the top edge of the right receiver wall, and this keeps the bolt head from turning as the bolt is operated. This groove ends short of the receiver bridge wall. When the bolt is fully open, the extractor lug can be pulled up and rotated into a slot in the receiver bridge— the bolt can then be removed. A small spring retainer, provided in the right side of the receiver extractor-lug groove, engages with the lip under the extractor lug when the bolt is fully drawn back. It prevents the bolt head from turning under normal operation of the bolt, yet allows the bolt head to be rotated manually to remove the bolt from the action.
The firing mechanism consists of a one-piece firing pin, coil mainspring and cocking piece. The bolt is drilled from the front, with the mainspring compressed between a collar on the front of the firing pin and a rear shoulder in the bolt body. The rear end of the firing pin is threaded into the cocking piece. A screw at the rear of the cocking piece prevents the firing pin from turning. Forward travel of the firing pin is stopped when the collar on the firing pin contacts the back of the bolt head, not by the cocking piece contacting the rear of the bolt.
An arm or tongue on the bottom of the cocking piece extends forward under the bolt body, into a raceway milled in the receiver, where it engages the sear and safety projecting into this raceway. The action cocks on closing the bolt, the sear engaging the front of the cocking piece arm and holding it back as the bolt is closed. The head of the cocking piece may be round and knurled, or flat and notched. There is also a half-cock notch (called “half-bent” notch in England) on the arm of the cocking piece; by firmly grasping the cocking piece, it can be lowered from the cocked position or drawn back from the fired position to engage the sear in this intermediate position. This locks the bolt and the sear. To fire the rifle in this half-cock position, the cocking piece must be manually pulled back to full cock. Originally designed as a safety measure, the half-cock notch serves no useful purpose. There is also a small stud or cam on top of the cocking piece arm which engages a notch cut in the rear of the bolt body. On raising the bolt handle with the action closed and the striker down, the notch engages the stud and pushes the cocking piece and firing pin back. The purpose of this arrangement is to prevent the firing pin from going fully forward unless the bolt is locked. In other words, the Lee-Enfield action cannot be fired unless the bolt handle is nearly all the way down and the action locked.
No. 1 Mark III action.
The safety is at the left rear side of the receiver. A flattened integral stud on the safety projects into the cocking piece raceway. Two shallow notches cut into the left bottom edge of the cocking piece arm can engage the safety when it is swung back. These notches are so spaced that one or the other is opposite the safety when the rifle is cocked or uncocked. When the action is cocked, the safety locks both the striker and bolt; when uncocked, it locks the bolt and pulls the firing-pin tip within the bolt head so that a blow on the cocking piece cannot discharge the rifle.
The bolt is locked by a small part threaded on the stem of the safety. The thread is multithreaded and left hand. Part of this bolt lock extends through the receiver wall to engage in a groove cut into the rear of the bolt body. As the safety is swung back, the threads force the bolt lock toward the right to engage a groove in the bolt and lock it. A spring bracket screwed to the receiver holds the safety in place. (In England
