In the early 1930s, a batch of 2,500 No. 4 Mk. I rifles were made for Trials. These were similar to the No. 1 Mk. VI but had a flat left side and did away with the chequering on the furniture. Observed examples are dated 1931 and 1933. Roughly 1,400 of these were converted to No. 4 MK. I (T) sniper rifles in 1941-1942 at RSAF Enfield.

By the late 1930s, the need for new rifles grew and the Rifle, No. 4 Mk I was officially adopted in 1941. The No. 4 action was similar to the Mk VI, but stronger and most importantly, easier to mass-produce. Unlike the SMLE, that had a nose cap, the No 4 Lee–Enfield barrel protruded from the end of the forestock. The charger bridge was no longer rounded for easier machining. The Iron Sight line was redesigned and featured a rear receiver aperture battle sight calibrated for 300 yd (274 m) with an additional ladder aperture sight that could be flipped up and was calibrated for 200–1,300 yd (183–1,189 m) in 100 yd (91 m) increments. This sight line like other aperture sight lines proved to be faster and more accurate than the typical mid-barrel rear sight elements sight lines offered by Mauser, previous Lee–Enfields or the Buffington battle sight of the 1903 Springfield.

The No. 4 rifle was heavier than the No. 1 Mk. III, largely due to its heavier barrel. A new bayonet was designed to go with the rifle: a Spike Bayonet, which was essentially a steel rod with a sharp point and was nicknamed “pigsticker” by soldiers. Towards the end of the Second World War, a bladed bayonet was developed, originally intended for use with the Sten Gun —but sharing the same mount as the No. 4’s spike bayonet—and subsequently the No. 7 and No. 9 blade bayonets were issued for use with the No. 4 rifle as well.

During the course of the Second World War, the No. 4 rifle was further simplified for mass-production with the creation of the No. 4 Mk I* in 1942, with the bolt release catch replaced by a simpler notch on the bolt track of the rifle’s receiver. It was produced only in North America, by Small Arms Limited at Long Branch in Canada and Stevens-Savage Firearms in the USA. The No.4 Mk I rifle was primarily produced for the United Kingdom.

Weight: 4.11 kg (9.06 lb) 

Length: 44.45 in (1,129 mm)

Barrel Length: 25.2 in (640 mm)