Boys anti - tank rifle The Rifle , Anti - Tank , . 55in , Boys commonly known as the " Boys Anti - tank Rifle " ( or incorrectly " Boyes " ) , was a British anti - tank rifle in use during World War II . It was often nicknamed the " elephant gun " by its users due to its size and large bore . There were three main versions of the Boys , an early model ( Mark I ) which had a circular muzzle brake and T - shaped monopod , built primarily at BSA in England , a later model ( Mk I * ) built primarily at Jonathan Inglis in Toronto Canada , that had a square muzzle brake and a V shaped bipod , and a third model made for airborne forces with a 30 - inch ( 762 mm ) barrel and no muzzle brake . There were also different cartridges , with a later version offering better penetration . Although adequate against light tank s in the early part of the war , the Boys was ineffective against heavier armour and was phased out in favour of the PIAT mid - war . Design and development . The eponymous creator of this firearm was Captain H . C Boys ( the Assistant Superintendent of Design ) who was a member of the British Small Arms Committee and a designer at the Royal Small Arms Factory , Enfield . It was initially called " Stanchion " but was renamed after Captain Boys as a mark of respect when he died a few days before the rifle was approved for service in November 1937 . A bolt action rifle fed from a five - shot magazine , the weapon was large and heavy with a bipod at the front and a separate grip below the padded butt . In order to combat the recoil caused by the large 0 . 55 inch ( 13 . 9 mm ) round , the barrel was mounted on a slide , and a shock absorber was fitted to the bipod along with a muzzle brake on the barrel . The Boys had been designed with numerous small narrow - slotted screws of soft steel set very tight into the body of the weapon and its repair and maintenance proved a nightmare for British ordnance repair crews . The cartridge was an adaptation of the . 50 BMG , with a belt added firing a 47 . 6 gram bullet . At its introduction , the weapon was effective on light armour ( 23 . 2 mm thick ) at 100 yards ( 91 m ) . There were two main service loads used during the Second World War : The W Mark 1 ( 60 g AP at 747 m / s ) and the W Mark 2 ammunition ( 47 . 6 g AP projectile at 884 m / s ) . The W Mark 1 could penetrate 23 . 2 mm of armour at 100 yards , about the thickness used on the frontal armour of a half - track or armoured car , or the side or rear armour of a light tank . Later in the conflict , a more effective round was developed , the W Mark 2 , which fired a tungsten - cored projectile at 945 m / s . The Boys ' effective range against unarmoured targets ( for example , infantry ) , was much greater . Despite its recoil slide and cushioned buttpad , the recoil of the weapon ( along with noise and muzzle blast ) was said to be terrific , frequently causing neck strains and bruised shoulders . Consequently , the Boys was almost never fired as a free weapon ( that is not affixed to a support ) except in emergencies . Service . The Boys rifle was used in the early stages of World War II against lightly armoured German tanks and combat vehicles . Britain also supplied a large number of Boys anti - tank rifles to Finland in 1939 and 1940 during the Winter War with the Soviet Union . The weapon was popular with the Finns , because it could deal with Soviet T - 26 tanks , which the Finnish Army encountered in many engagements . Although useful against early German and Italian tanks in France and North Africa , such as the Panzer I , Panzer II and early models of Panzer III , increases in vehicle armour during the Second World War left the Boys largely ineffectual as an anti - tank weapon . A shortened version was issued in 1942 for issue to airborne forces and saw use in Tunisia , where it proved completely ineffective because of the reduced velocity caused by the shortened barrel . The Boys was so unpopular that the Canadian government commissioned a Disney training film , " Stop That Tank " , to oppose the rifle ' s " jinx " reputation . Nonetheless , in the European theatre it was soon replaced by the PIAT ( Projector , Infantry , Anti - Tank ) in 1943 , which first saw service during the Allied invasion of Sicily . In other roles the Boys saw some use against bunkers , machine gun nests and light - skinned vehicles but was rapidly replaced in British and Commonwealth service by the U . S . . 50 BMG calibre M2 Browning machine gun as quantities of the latter weapon became available . Using armour - piercing ( AP ) , armour - piercing incendiary ( API ) , and armour - piercing incendiary tracer ( APIT ) ammunition , the . 50 Browning was just as capable in armour penetration and more devastating when igniting thin - skinned vehicles using incendiary rounds than the Boys , but the Browning could also serve as an effective anti - aircraft weapon . Even the British Special Air Service , which made much use of captured or cast - off weapons for their jeeps and reconnaissance vehicles , quickly got rid of their Boys rifles in favor of . 50 M2 Brownings or the Italian 20mm Breda cannon . The weapon was standard issue to British and Commonwealth forces which attempted to stem the Japanese onslaught through the Pacific theatre . At Milne Bay , the weapon proved completely ineffective . It also failed to stop Japanese tanks in Malaya . Some accounts claim that the 1 / 14th Punjabi s knocked out two light Japanese tanks at a roadblock . This claim , however , has never been substantiated from the Japanese side . During the Battle of Singapore the 1st Cambridgeshire Regiment claims the Boys was very useful in knocking holes through walls during street fighting . Again , however , Japanese sources do not substantiate the claim . The US Marine Corps purchased Boys rifles prior to the attack on Pearl Harbor . They were used in the Philippines and by the Marine Raider Battalions against enemy bunkers . The Boys rifles was used by the local Filipino soldiers under the Philippine Army and Philippine Constabulary during World War II under the Japanese Occupation of the Philippines from 1942 to 1945 and Post - War era from 1945 to 1960s including Hukbalahap Rebellion ( 1946 – 1954 ) and the Philippine Expeditionary Forces to Korea ( PEFTOK ) during Korean War ( 1950 – 1955 ) . The Boys rifles were also used by the Chinese Nationalist Army during the late Second Sino - Japanese War in both China and Burma . In September 1965 , members of the IRA hit the British fast - attack patrol boat HMS " Brave Borderer " with a Boys rifle , crippling one of her turbines while she was paying a visit to Waterford , Republic of Ireland . Usage . Vehicle mounting . The Boys Rifle was sometimes mounted on vehicles such as the Universal Carrier ( " Bren Gun Carrier " ) , Humber LRC and the Standard Beaverette armoured car .