When the British Army adopted the 7.62mm round it still had vast quantities of Bren light machine guns in store. The Bren gun was still an excellent light machine gun and these weapons had many years of life left in them. It was decided to convert the weapon to the new calibre and the L4 light machine gun was born in 1955-56.

Converting a firearm is more complicated than just adding a new magazine and barrel and the L4 needed a new barrel, revised magazine housing, reinforcement of the chamber walls to help support the magazine lips and a revised flash hider. The new weapon was a cost effective solution to the need to adopt a light machine gun and was to remain in service through until the Gulf War in 1991. A number of different marks of L4 were used, the example tonight however is the L4A3 variation:

The first and most obvious feature is the revised magazine, which is far straighter than the Bren gun as the 7.62mm round is rimless, whilst the .303 round has a large rim:

Note the circular reinforcing plate under the magazine well. This was a plug inserted on both sides of the receiver to help support the magazine feed lips. An insert was fitted into the magazine well to allow the shorter round to be fed into the weapon and to give the correct geometry to accurately feed rounds from the magazine into the gun:

One of the primary design features of the L4 was that it should be able to use the twenty round SLR magazines which it can do easily as the feed lips of both the L4 and SLR magazines are identical. The cocking handle is on the right side of the receiver and is of the folding type. When not in use it lays flat against the body of the gun, but folds out to cock the weapon:

The other major and obvious distinctive feature of the L4 is the barrel. The new barrel does away with the Bren gun’s conical flash hider and replaced it with a cage type, simlar to the SLR:

The carry handle for the L4 is also distinctive, having circular lightening holes drilled through it’s collar where it goes around the barrel:

The bipod on the L4 has a pair of height adjustable feet. Pressing in the spring loaded tab allows them to be drawn out, the angled cuts offering a wide variety of height settings:

Other changes included adding a new style of butt:

And a new rear sight that is calibrated for 7.62mm ammunition:

As these weapons were built on old Bren receivers, they retain the old Bren gun’s markings, but these have been struck through:

From this we can see that it was originally a 1944 produced Bren Mk II. The new receiver markings and designation are now stamped on the opposite side of the receiver:

The old serial number behind the sight has been struck through and a new serial number stamped on:

The L4 remained in use throughout the troubles in Northern Ireland, the Falklands and even saw some rear echelon service in the First Gulf War when it was used as a pintle mounted vehicle weapon. This L4A3 was one of 7,600 made in the late 1950s. It was factory refurbished in the late 1980s and placed into reserve stocks in case of a future conflict. It came straight from store to be deactivated and is in virtually mint condition.