United Kingdom (1940)
Light Anti-Tank Gun – 3,000 – 4,000 Built
The Ordnance, Smooth-Bore, 3in, Mk. 1 ‘Smith Gun’ was an expediently designed light anti-tank gun that served with the British Home Guard during The Second World War. In an effort to quickly replace the equipment lost during the British evacuation of France at Dunkirk, almost any and all weapon designs from all manner of places came under consideration by the War Office (WO) – necessity is the mother of invention, after all. Designed by retired British Army Major William H. Smith, the officially long-winded ‘Gun, 3in, Ordnance Smooth-Bore’, simply known as the ‘Smith Gun’ or ‘3-inch OSB’, was one such expediently designed weapon.
Thought up as a light anti-tank gun, the ‘Smith’ was one of many ‘pipe-guns’ adopted by a weakened British Army facing a possible invasion of Great Britain. Other similar somewhat ad hoc weapons from this period include the Blacker Bombard and the Northover Projector. The gun’s simple yet ingenious design allowed it to simply be tipped into firing or towing position, and was light enough that it could be towed by civilian car, motorcycle, or even a horse. The ‘Smith Gun’ would only see limited use by the regular army, and would never fire a shot in anger. It built up a poor reputation of safety, with many saying “the only thing it killed was its operators”. Despite this, the gun would become a valuable artillery piece in the arsenal of Britain’s wartime civilian volunteer army, the Home Guard.
For The Want of a Gun
The series of unfortunate events that led to the evacuation at Dunkirk in May to June 1940 had left the British and Commonwealth Army battered and bruised. Not only had they lost men as they backtracked through France, but they had also left behind hundreds of tons worth of equipment. Trucks, tanks, guns, and artillery pieces were all left behind as the Wehrmacht dogged them to the coast. With the evacuation complete, Britain prepared itself for the prospect of invasion – Hitler’s planned Operation Sealion. Having lost so much equipment, Britain was at somewhat of a disadvantage. The British Army was severely weakened, with estimates that only 27 full-strength divisions of the regular army could be raised to defend Britain. With 840 anti-tank guns left in France, the Army had 167 guns and limited ammunition stocks to spread between them.
Just days before the evacuation of Dunkirk, with the Wehrmacht Blitzkrieging their way through Europe, the British Secretary of State for War, Anthony Eden, made a radio broadcast on 14th May 1940:
“Since the war began, the Government have received countless inquiries from all over the Kingdom from men of all ages who are, for one reason or another, not at present engaged in military service, and who wish to do something for the defense of the country. Now is your opportunity. We want large numbers of such men in Great Britain who are British subjects, between the ages of 17 and 65, to come forward now and offer their service in order to make assurance doubly sure. The name of the new force which is now to be raised will be the ‘Local Defence Volunteers’ [LDV].”
– Anthony Eden, 14th May, 1940.
Over 250,000 volunteered for this new LDV in the first week, numbers that only increased with the events at Dunkirk. This ‘civilian army’ was initially armed with weapons of their own possession or making and were without uniform (save for an LDV armband). The force would later receive arms and uniform, and be trained to become an effective fighting force known as the Home Guard. A problem soon arose with giving the Home Guard effective anti-tank weapons, with the regular army coveting what remained of the existing anti-tank gun stock and the accompanying ammunition, the War Office revisited previously ignored weapon designs and patents.
One such design had been submitted by William H. Smith, a retired Army Major, who was now managing Director of the structural engineering firm Trianco Ltd.. The weapon was designed with ease of manufacture and affordability in mind. Its unorthodox design left the Ordnance Board skeptical, not necessarily wanting to approve it for service. However, after a display of the weapon to Prime Minister Winston Churchill in 1941, he himself ordered that it be placed in production.
Unorthodox Design
Smith’s design came in two parts: the gun itself and a similar ammunition limber. In tow, the weapon rolled on two large wheels – one flat, the other concave – between which sat the gun and its shield, with a towing eye attached directly to the muzzle of the gun. The ammunition carrier was much the same, with capacity to carry 20 – 40 rounds, with the gun itself able to carry 5 – 10 rounds.
Weighing in at a combined 965 pounds (438 kg), the gun (606 lbs/275 kg) and limber (360 lbs/163 kg) were just small and light enough to be dragged together via car or truck, or split between two motorcycles or horses, although this was not outlined in its design, and was merely discovered by Home Guard units equipped with the gun. They were later discouraged from doing this, as it was found to severely damage the wheels and axles, effectively knocking the gun out. Due to a lack of ammunition for the gun, however, the limber became largely unused, leaving it available for spare parts.
Bringing the OSB into action was as simple as tipping the gun and limber on their sides, with the flatter left wheels forming bases. These wheels had six blades around the internal circumference that allowed it to dig into soft ground for stability. The upper wheel formed ad hoc over-head protection, while the gun shield was wide enough to cover the gun crew. Now sitting vertically on its axle at about 4 feet (1.2 m) high , the gun was capable of 360º horizontal traverse, achieved manually by the operators. The weapon also had a maximum elevation of 40º, allowing shells to be effectively ‘lobbed’ onto target due to its low muzzle velocity. The gun was operated by a 4-man crew, designated as No. 1 to No. 4.
- No. 1: Gun commander
- No. 2: Responsible for ammunition and limber
- No. 3: Breach operator/gunner
- No. 4: Driver, also responsible for the ammunition
Firepower
As made clear by the officially long designation of the weapon, the diameter of the bore was 3 inches (76 mm), with a barrel length of 54 inches (1.4 m). It was low velocity, and, despite being designed with a maximum range of 1,600 yards (1,500 m) in mind, its effective/accurate range was found to be just that of between 100 and 300 yards (90–270 m).
The weapon could use 4 different types of projectile, the primary being an anti-armor shell. This was a fin-stabilized High-Explosive Anti-Tank (HEAT) shell that weighed 8 lbs (3.6 kg). It had a maximum range of 200 yards (183 m), but it was found best accuracy was achieved at just 100 yards (90 m). The HEAT shell was rather powerful for its size, able to penetrate 3.15 inches (79 mm) of armor plate, or put a sizable hole in a nine-inch reinforced concrete wall.
The other main shell type available to the OSB was a 10 lb cast-iron fragmentation high-explosive ‘bomb’ with an accurate range of 150 yards. The weapon could also fire 3 in High-Explosive (HE) and Smoke mortar rounds. Being smooth bore, it was theoretically possible to fire anything from it, as long as you had a charge to back it. In total, 10 of the 8 lb shells, or 5 of the 10 lb shells could be carried on the gun itself, and 40 8 lb, or 20 10 lb shells could be carried on the limber.
Comparatively speaking, the best contemporary weapon to the Smith OSB would have been the Army’s trusty 2-pounder (40 mm) anti-tank gun. It could be said that the ‘Smith’ had two large advantages. Firing its Armor-Piercing shot, the 2-pounder could penetrate 2 to 2 ⅜ inches (50 to 60 mm) of armor, while the ‘Smith’ could punch through 3.15 inches (79 mm). Plainly, the ‘Smith’ had better anti-armor performance, but was also equipped with a powerful anti-infantry shell, something the 2-Pounder gun was rarely equipped with. Operationally speaking, the 2-pounder was also larger than the Smith, and much heavier at 1,795 lbs (814 kg). However, it suffered from a far smaller range and poorer accuracy, both of which made the 2-pounder the mainstay of British anti-tank forces for the early war period.
Production and Adoption
An order was placed for 6,000 ‘Smith Guns’ and accompanying limbers late in spring 1941, to be complemented by 2,600,000 rounds of ammunition. Despite the commencement of production at the start of 1941, the gun would not actually be issued to Home Guard units until the following year, in February 1942. By early 1943, just under 3,050 OSBs had been produced. There were lengthy delays in the production of ammunition, leaving many of the guns to be issued with just 8 rounds of either the anti-tank or anti-personnel type. This lack of ammunition made live-fire training an exception rather than rule.
The War Office effectively sold the ‘Smith’ to the Home Guard as a “simple, powerful and accurate weapon which, if properly handled, will add greatly to the firepower of the Home Guard.” However, it had a number of flaws that left the majority of Home Guard members despising the weapon during the early years of its adoption. Perhaps what made them sneer at the OSB most was its reputation for killing its operators. This reputation came from its short service life with the Royal Air Force (RAF) Regiment, which employed it as an airfield defense. During a training exercise, Corporal Cecil E. Maynard of 2819 Squadron, RAF Rgt., was killed when the OSB he was operating blew up. It was thought that a faulty fuze was the culprit.
Despite the initial distain, the Home Guard eventually grew fond of the gun, with many calling it “one of the best pieces of equipment ever issued to the force”. The ‘Smith Gun’ fell under the designation of ‘Sub-Artillery’, essentially small-bore artillery meant for defensive use by the Home Guard. It was not the only weapon equipped to the Home Guard that came under this designation. Other examples included the ‘Blacker Bombard’ (a 1.14 in/29 mm spigot mortar), and the ‘Northover Projector’ (a 2.5 in/64 mm grenade thrower). The OSB would stay in the service of the Home Guard until the force was stood down in winter 1944, after the threat of a German invasion was over. The following year, the ‘Smith Gun’ would be retired and declared obsolete.
Smith Gun Carrier
Again, with the fear of invasion weighing heavy on the War Office, an attempt was made to effectively make a self-propelled ‘Smith Gun’. This was done by converting the venerable Universal Bren Carrier. The gun was stripped of its integral carriage and placed at the front left of the Carrier, in a new superstructure. It had limited horizontal traverse, but presumably retained the vertical traverse range of the standard gun. This vehicle was a one-off experiment to create an ad-hoc self-propelled anti-tank gun, and unfortunately not much survives of its history. Clearly, the vehicle did not progress any further than the prototype phase.
“We Know Our Onions”
Weapons and equipment that did not feature in the fighting of the Second World War are often overlooked and forgotten. This was the case of the Smith Gun until the 1970s. The much-loved classic British comedy TV series Dad’s Army (1969 – 77), which was based on the Home Guard, often featured stories or equipment inspired by real events. In 1973, Episode 4 of the 6th Series featured a ‘Smith Gun’. The episode – titled “We Know Our Onions” – follows the platoon as they embark on a training exercise with their newly issued ‘Smith Gun’. Part of the exercise involves the men defeating obstacles to gain access to training ammunition for the gun. They fail to clear the obstacle, so load the gun with onions instead. Effectively acting as grape-shot, the platoon successfully repelled a small unit of attacking regular army troops. Although a fanciful plot, it was based on a real account of a Home Guard platoon loading their Northover Projector with apples!
Conclusion
The ‘Smith Gun’ is a prime example of the old adage, “necessity is the mother of invention”. While it had some catastrophic teething problems, the volunteer soldiers of the Home Guard grew rather fond of it as the war went on. How effective it would have been in combating an advancing hoard of German Panzers is another matter. It certainly would have put a sizable hole in the typical tanks of Blitzkrieg, such as Panzer IIs and early model Panzer IIIs and IVs.
Despite the obscurity of this weapon, several still survive, not least in the collections of the Imperial War Museum and Royal Armouries. Individual examples can be found at the RAF Regiment Heritage Centre, Suffolk, and the National Army Museum, London.
Illustration by Oussama Mohamed ‘Godzilla’.
Sources
Home Guard Instruction No. 51, Battlecraft and Battle Drill For The Home Guard: Part IV, The Organization of Home Guard Defence
Brigadere-General A. F. U. Green, The British Home Guard Pocketbook, 1942
Popular Mechanics, Dec. 1944
S. P. Mackenzie, The Home Guard: A Military and Political History. Oxford University Press, 1995
D. M. Clarke, Arming the British Home Guard, 1940-1944, Cranfield University, 2011
David Fletcher, Tony Bryan, New Vanguard# 110: Universal Carrier 1936–48: The ‘Bren Gun Carrier’ Story, Osprey Publishing, 2005
