Lahti L - 39 " Norsupyssy " The Lahti L - 39 " Norsupyssy " was a Finnish anti - tank rifle . Description . The L - 39 antitank rifle ( official Finnish designation 20 pst kiv / 39 , unofficial " Norsupyssy " - elephant gun ) was developed by famous Finnish arms designer Aimo Lahti on request from Finnish army . Early prototypes were built around proprietary 20x113 ammunition , also designed by Lahti , but in mas production this was changed to more common 20x138B ammunition , which was more powerful , has wider selection of loadings ( AP , AP - T , AP - HE , Incendiary etc . ) , and was also common with 20mm AA guns , bought from Germany . About 1 800 of these guns were produced by VKT factory during the WW2 , and although 20mm shells were rather ineffective against Soviet T - 34 and KV tanks , Finnish army made a good use of this weapon to fight light armor , bunkers and other targets of importance . In 1944 , an ' anti - aircraft rifle ' , known as 20 it kiv / 39 - 44 , was developed from the L - 39 , by adding select - fire capability and simple anti - aircraft mount . It must be noted that Finnish army kept its stocks of Lahti L - 39 anti - tank rifles well after the WW2 - many were surplussed and sold to USA in early 1960s and last ones were scrapped or sold as surplus in mid - 1980s . Lahti L - 39 anti - tank rifle is a semi - automatic , gas operated weapon . Gas piston is located below the barrel , and a manual gas regulator is provided in gas block . The bolt locking is achieved by vertically sliding locking block , which is installed in the bolt . When in battery , this locking block is forced up by cam surface in the bolt carrier to engage the slot cut in the receiver . After discharge , rearward movement of the gas piston and bolt carrier forces the locking block to fall down and unblock the bolt ; after that , bolt is free to recoil along with bolt carrier . One unusual feature of the Lahti L - 39 anti - tank rifle is that bolt remains open after each shot , which allows the barrel to cool down faster after each shot . Despite that , gun is fires from closed bolt , and the firing sequence after each shot involves two deliberate actions . First , shooter must squeeze grip lever ( located below the trigger guard ) to release bolt forward . Once bolt is fully locked , shooter can pull the conventional trigger and fire the gun . Feed is from detachable top - mounted magazines , ejection is to the bottom . To reduce the felt recoil , rifle is equipped with massive muzzle brake and a soft shoulder pad . Standard iron sights are fully adjustable and calibrated between 200 and 1400 meters . Lahti L - 39 anti - tank rifle was equipped with unusual " dual " bipod , with two sets of legs , one with spiked shoes for use on more or less hard ground and another with skid - type shoes for use on soft ground or snow . Combat History . During the Winter War , Finland suffered from the lack of anti - tank weapons . Only two rifles and a few 20 mm 13 . 2 mm machine guns were sent to the front , where machine guns proved ineffective and unreliable , while the 20 mm guns successfully fought Soviet tanks . The gun was also widely used in the tactic " Cold Charlie " , which employed a Finnish dummy to simulate an officer checked out , which attracted the Soviet sniper fire , then the Lahti L - 39 was used to eliminate the Soviet sniper . Although this gun could not penetrate the armor of the new Soviet tanks like the T - 34 and KV - 1 used in Continuation War , proved to be quite effective against the pockets of bunkers , targets located at great distances and even airplanes . A small amount of a fully automatic version of the L - 39 was produced for use as anti - aircraft gun . Other preferred targets were snipers and the various weaknesses of the tanks , as the hatches open , especially if used ammunition white phosphorus . It was even capable of damaging the tank turrets and block the lifting mechanism of the canyon . The shooters found that L - 39 was difficult to carry in combat . Your charger weighed almost two pounds more than the SMG Suomi M - 31 . The complete rifle weighed about 50 kilograms and was generally towed by reindeer or horses , but could also be carried by several men . In combat it required a team of two men moving and firing the gun . Some guns were simply abandoned in the middle of the battle , because it ' s easy to be replaced . By the end of the war , more than 1900 L - 39 anti - tank guns had been manufactured by VKT ( Valtion Kivääritehdas , " State Rifle Factory " in Finnish ) and used in combat . Several of these anti - tank rifles were on active duty after the Second World War as anti - helicopter weapon , while others were sold to collectors , mostly from the United States . Today these anti - tank rifles , especially those who still work , are very scarce and sought after . Some anti - tank guns off ( by welding a steel rod in the chamber ) were reactivated because of their value . As ammunition is extremely difficult to obtain , they are frequently recalibrated to use cartridges . 50 BMG and thus lower the cost of their employment . In the United States , possession of such guns by civilians is possible , depending on federal and state . Since this gun fires bullets of a caliber greater than 12 . 7 mm , is considered a " destructive device " is subject to the Act and National Firearms 1934 . Its possession by civilians depends on the law and each state regarding " destructive devices . "