In-depth: BSA’s prototypes

During World War II, Birmingham Small Arms produced a number of experimental weapons that were submitted to the Ordnance Board for testing. None were successful, but each is interesting in its own right. BSA had a reputation for good quality but their products were also more expensive than some of their competitors as a result. They were also unafraid of innovation, as this post will detail.

In May 1938, BSA was commissioned by the Ordnance Board to produce a prototype of a design sent to them by Dinely & Dowding. The design was the work of Pal de Kiraly, a Hungarian engineer. BSA, in conjunction with Kiraly, produced a batch of prototypes at the cost of £5 a unit and sent them to the Ordnance Board for testing. There were two versions: a long-barreled one and a short-barreled one. It was chambered in 9x25mm Mauser and had a magazine size of 40 rounds. The large magazine size gave Dinely the idea of a pivoting magazine housing, which Kiraly agreed upon, although this feature was not incorporated on the initial prototypes.

The BSA-Kiraly prototype. Reportedly an excellent weapon, although very few were made. It served as the basis for the Hungarian 43M submachine gun.

The trigger mechanism of the weapon was one of the most complex ever produced. It used a flywheel mechanism to keep the fire rate low. Wrapped around the flywheel was a strip of steel tape connected to a spring. When the bolt moved backwards, it would strike the flywheel, which would rotate and then be returned to its original position by the spring. When it reached its original position, the bolt was released and flew forward. Kiraly was open to simplifying the mechanism to reduce production costs.

Detail of the BSA-Kiraly’s trigger mechanism.

The BSA-Kiraly prototypes were tested and it found to be a quality weapon that performed very well. Despite this, the Ordnance Board did not investigate it any further. They showed little interest in submachine guns until the British Army’s experiences at Dunkirk in 1940.

This submachine gun designed by Mark Dinely was considered before WWII by the Ordnance Board. Ultimately it was not developed any further.

Another BSA design that the Ordnance Board showed early interest in was an SMLE conversion. This was actually designed in 1916 by Mr. N. Howell and manufactured by BSA but it was not until 1940 that the weapon was considered as an anti-aircraft gun for the Home Guard. Despite this, it was never actually issued.

The Howell rifle. It had a gas tube to allow for automatic fire. Though cheap to produce, it was not very practical.

Detail view of the Howell rifle.

The Ordnance Board approached Birmingham Small Arms to design a replacement for the Bren gun in the event that RSAF Enfield was bombed by the Germans and production of the Bren consequently ceased. Fortunately this never happened, but a prototype was produced as an emergency precaution. Designed by Harry Faulkoner, the chief designer at BSA, the BESAL was a bare-bones machine gun that cost very little to manufacture. It had a rectangular breech block that did not tilt like the Bren. The return spring, located under the barrel, was compressed when the breech block was carried backwards by the piston. The weapon was fed through Bren magazines and was cocked exactly like the Bren.

A Mk.2 model was also made which had a modified cocking system that would be re-used in a later BSA design, the BESA machine gun. The BESAL Mk.2 was cocked by sliding the pistol grip forward, which would engage the piston, and then pulling it back, which would retract the piston with it.



The BESAL Mk.I was designed as a stop-gap weapon, as is evident from this picture. It used Bren magazines.

The BESAL Mk.2 took design cues from Czech weapons, specifically the ZB Vz.60. Like the Mk.I, it never saw military use.

The BESAL was tested and by all accounts performed well considering the cheap cost. The Ordnance Board seriously considered it for a Bren substitute, but the need never arose. When the BESA was designed, the BESAL’s name was changed to simply the Faulkoner machine gun to avoid confusion.



In late 1942, BSA designed a new submachine gun on request of the Special Operations Executive. It was designed by Mr. Norman and took its name from Welwyn, where the SOE were situated. On February 24th 1943 the Ordnance Board were made aware of the Welgun and wanted to test it.

Commissioned by the SOE, the Welgun looked conventional but internally was anything but. The stock folded over the top.

The Welgun was cocked by a pulling back a milled groove that was fitted around the bolt, which had two forward extensions that ran along the barrel connected together by a ring that formed the housing of the return spring. The return spring was wrapped around the barrel and compressed when the weapon was cocked. The firing pin was retracted by a spring and operated by a plunger which protruded from the bolt face. When the bolt closed the firing pin was pushed forward as the plunger retracted back into the bolt. The safety system was also unusual. It consisted of a lever-and-hook mechanism that would prevent the bolt from moving when it was closed. If safety was applied when the bolt was cocked then the hook would hold the bolt back.

The Welgun was tested at Pendine in February 1943 against the Patchett and the Sten Mk.IVA, with the Sten Mk.II and the Lanchester Mk.I being used as test controls. Three Welguns were used and they exhibited the best accuracy of the weapons tested. However, they could not sustain cold temperature tests. Further trials in September and October 1943 saw the Welgun perform poorly and interest in the design had diminished. Of all the weapons offered, was considered the lowest-priority submachine gun by the Ordnance Board. No further development took place.

Another weapon designed by Mr. Norman for the SOE was the self-titled Norm carbine. It shared some similarities to the Welgun in terms of design and incorporated a pistol-like milled slide for cocking. The ergonomics were bizarre. The foregrip protruded horizontally to the right of the muzzle. The user was supposed to grip it with their left hand whilst their arm passed underneath the barrel. A heat guard was fitted to the underside of the barrel to prevent it from burning the firer’s forearm. The stock could be folded inwards but not vertically. The butt stock ran through a hollow tube fixed to the bottom of the pistol grip. There are no records of the weapon being used.

The Norm Mk.I. Similar to the Welgun, the Norm carbine was purely experimental and never considered for military use.

Also in 1943, BSA made a prototype of an Australian design. It was made at the request of a Mr. Andrews and was not commissioned by the Ordnance Board. The resultant weapon was very unusual. It consisted of a very short and wide rectangular body which internally contained two return springs mounted on rods that ran through the bolt to two ports above and below the barrel. It had no conventional stock but instead a dummy magazine well fixed to the rear that the user could slot a spare magazine into. The spare magazine could act as a rudimentary stock although this was very uncomfortable and it was liable to fall out.

Despite being a private venture, the BSA-Andrews was trialed at Pendine on October 5th 1943 against the Welgun, the Patchett, the Sten Mk.IVB, the Austen, and the Owen. The Andrews was criticized for its uncomfortable ergonomics and there was no military interest in the weapon.

The BSA-Andrews. Very uncomfortable to hold and awkward to operate.

Towards the end of the war, BSA developed a new submachine gun that was first demonstrated on April 12th 1945 at Enfield. The weapon tested was the first version which would later be known as the Mk.I. It was a unique weapon of which there are scarcely any similar designs that came before or after it. Instead of a conventional cocking slot, it had a large plastic sleeve that wrapped around the barrel and acted as the fore grip. This sleeve was pumped forward to cock the weapon. Four Mk.Is were tested and fired 950 rounds each without any major issues. It was tested again throughout October and the conclusion drawn from these tests was that it was a promising design. The Ordnance Board showed considerable interest.

The BSA Mk.I, designed in 1944. It is shown here mid-cocking. The fore end would be pulled back to fully cock the weapon.

The BSA Mk.I, exhibiting the compact design. Note the folding magazine housing and straight magazine. These were ditched in the Mk.II.

It was not until June 1947 that military trials would commence. The BSA by this point had been improved as the Mk.II, which had curved magazines and a redesigned cocking sleeve. The new Mk.II was tested against the MCEM-3. It fired at 530rpm but was slightly over the weight specified by the General Staff Specifications. Nevertheless, it was favored over the MCEM-3. Afterwards it was tested against the Australian MCEM-1 designed by Major Eric Hall and once again came out favorable.

Full trials took place at Pendine in September 1947. The BSA Mk.II was tested against the Patchett Mk.II, the MCEM-3, and the Australian MCEM-1. Two Sten Mk.Vs were used as test controls. The BSA came out best and the Ordnance Board ordered 100 units, but BSA only managed to manufacture 6 since production costs were so high.

The BSA Mk.II. The cocking sleeve had been redesigned and the magazine was now curved. It was designed in 1947, not 1949 as is sometimes said.

By 1951, further trials were scheduled to take place, but the General Staff Specifications were updated and now demanded that the weapons submitted have bayonet fittings. This was not previously a requirement and both the BSA Mk.I and Mk.II models were completely incompatible with a bayonet. This presented a big problem for BSA, who could not realistically produce bayonet fittings without completely redesigning the fore end. But to do so would also mean redesigning the cocking sleeve. The resultant model was known as the Mk.III and was tested against the Patchett Mk.II, the Australian MCEM-2, and the Madsen M50 in May. The redesigned cocking sleeve of the Mk.III proved unreliable and too stiff, and the weapon failed a sand test. The Madsen and the Patchett came out the best and the Army decided that it was most likely to adopt the Patchett. BSA felt that the new General Staff Specifications had sabotaged their chances and demanded a retrial, which the Ordnance Board reluctantly agreed to. The retrial took place in 1952 and the Madsen came out best. The BSA design was rejected and the Army would officially adopt the Patchett gun in 1953.

The BSA Mk.III. The trigger had been redesigned and the barrel now protruded from the cocking sleeve to allow a bayonet to be fitted.

BSA also developed experimental rifles for rifle trials that took place after World War II. Their main dog in the fight was their 28P rifle, which was chambered for the new .280 caliber. It was designed by Claude Perry. The Ordnance Board preferred the more modern designs that were coming from RSAF Enfield and the 28P was not considered high-priority. During trials in 1950, the 28P’s breech exploded. It was rejected in favor of Enfield’s EM-2, with a very limited production run.

Experimental BSA bullpup rifle developed in 1946.

Having failed to secure a military contract, BSA focused on motorcycle design until it was bought out in 1973.

