The German invasion of the Soviet Union in 1941 brought about many strange vehicles from both sides. From the improvised ZiS-30 built by the Soviets to the Sturer Emil fielded by the Germans the quest for firepower saw a wide variety of concepts pressed into service. Unlike the majority of these which only featured a single cannon, though, one design built within the factories of the Red Army would attempt to change that. This is the story of the Soviet three headed dragon, the KV-7. The Kliment Voroshilov,or KV, series of vehicles would serve as the armored shield of the Red Army following its success in the Winter War against Finland. Not only would turreted variants such as the KV-1 and KV-2 see service, but the chassis would be used for a variety of self propelled guns including the KV-7. Many of these vehicles are among the over 2,500 tanks, planes, and ships within the 10 nations featured in today’s sponsor War Thunder. 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When you think of Soviet self-propelled guns during the Second World War you likely picture vehicles such as the SU-152 or ISU series. Though these are by far the most well known of their SPGs they would not be the first designs built on a heavy tank chassis. That honor would instead fall to a far more unusual vehicle known as the KV-7. Unlike a more traditional design of that period such as the successful German Stug III this new tank would be fitted with not one, but three guns. Development of this design would begin in November of 1941 within the walls of the Chelyabinsk Kirov Factory. Reportedly this would begin by order of Stalin himself calling for a KV-1 equipped with a 76mm F-34 cannon and two 45mm cannons in a triple mount. Unlike a similar design based on the T-34 from around the same time which would have fitted this into a turret, the KV based design would instead use a fixed mount within a casemate. While the T-34 design would never leave the drawing board the KV-7 saw considerable development. As with many other Soviet projects of that period work proceeded rapidly with the first prototype completed early the following month on December 10th. The layout of the KV hull remained largely the same for the KV-7 with a driver and hull machine gunner in the front, followed by a fighting compartment and a rear mounted engine and transmission. The fighting compartment replaced the turret with a box-like structure with room for four men, a gunner, commander, and two loaders. These loaders fed the three guns in the U-13 gun mount from a supply of 93 rounds for the 76mm and 200 rounds for the 45mm guns. This gun mount theoretically allowed the guns to be fired individually or all at once in a salvo. Additionally the tank featured two machine guns mounted in the hull front and rear of the fighting compartment with a total of 3,591 rounds of ammo being carried. Access in and out of the vehicle was to be done through the two hatches on the roof, although the driver did also get an emergency escape hatch under his seat. As shown by this photo the roof was installed by bolting it in place rather than welding it. As for protection this vehicle had 75mm of frontal armor on the hull and casemate further increased by additional plates. These increased the frontal hull to 100mm and the “turret” to 105mm. The gun shield also featured 100mm of armor. The sides of the lower hull remained the same as the original KV although the casemate sides were made of 60mm plates. The front and sides of the casemate were also angled slightly which further added to the protection they offered. Between this new armament and the new armored fighting compartment this brought the weight up slightly with it weighing around half a ton more than the KV-1 at 47.5 tons. Initial plans for this design were quite bold with talk of 1 out of every 5 KVs produced being a KV-7. An initial batch of tanks would begin production by late December with up to 20 hulls being completed. As testing of the prototype continued though this design quickly began to reveal its flaws. The main problem found with the design was that the triple gun arrangement proved to be inaccurate. This was due to several factors including the guns being different calibers meaning at range a single target could not be engaged by all three guns simultaneously. The salvo ability itself also proved problematic with it unable to fire a volley of all three guns. One source also indicates that firing of the side guns caused the sight to be knocked out of alignment with the gun, however this may be referring to the later variant of the vehicle with twin ZiS-5 guns. The armor of the vehicle was also deemed insufficient with an increase of the hull front armor to 110mm and the casemate front to 115mm or 120mm being suggested. The fire rate of the tank proved to be acceptable though along with the mobility of the vehicle. As just mentioned the idea of swapping in a new twin gun arrangement to replace the 3 gun one was also considered. This would occur shortly afterwards with Stalin issuing an order to cancel the triple gun KV-7. Still under the same designation of KV-7 the design of the vehicle remained the same aside from the armament. Known as the U-14 this consisted of the aforementioned twin 76mm ZiS-5 guns. Work on this design began in late January with it continuing through early 1942. Testing of this design found it to be just as flawed as the former one with the traverse requiring two hands and issues with the placement of ammo storage being noted. Some work on the design would pick back up later in the year during October with some proposals for improvements to the design. None of these seem to have occurred though and the prototype was left to gather dust. As for what happened to the other KV-7s which began production it is unclear. While it failed to reach combat the legacy of the KV-7 was not entirely one of failure as it would help inspire another design. Around the same time the twin 76mm armament was being developed another proposal was put forward. Rather than multiple guns as the other mounts called for this would consist of a single 152mm M-10 howitzer. The development of a self propelled gun armed with a 152mm or other large guns had already been considered with earlier projects and even saw production with the KV-2. This style of bunker buster was something the Soviets saw great value in and the KV-7 was seen as a potential option for such a design. Work on this would continue alongside the ZiS-5 armed variant, with several different proposals being put forward. One, known as the ZIK-20 featured a completely new casemate style. The story of that vehicle deserves a video of its own though. Development of that design and others would pick up where the KV-7 left off with them eventually reaching production in the form of a vehicle which became known as the SU-152. From an unusual gun configuration to a progenitor of the SU and ISU type of vehicles the story of the KV-7 was a mixed one. The entire concept of the vehicle on the surface seems promising allowing for increased firepower within the same footprint. As discussed in my previous video on double barrel tanks though this idea comes with its own problems over a single gun design. The KV-7 shows us some of these with the accuracy issues it suffered from. Testing also revealed that although the practical fire rate of the vehicle was roughly that of a traditional tank with 5-6 volleys per minute for the three gun design and 6-7 shots per minute for the twin gunned example. This would still consist of more rounds down range, but if the accuracy meant that more often than not those shots would miss, is this really an advantage? The 76mm armament would also have quickly begun to lose its effectiveness against enemy armor as the Germans introduced new Panzer types in the coming years. In the end the KV-7 was little more than a failed experiment among many other concepts tested by engineers during the Second World War. But what do you think of the KV-7? Was it a concept which should have seen more development or just a waste of time and resources? Let me know in the comments, and while you’re down there don’t forget to try out War Thunder for free on PC, Xbox, and Playstation using my link to get your special bonus for both new and returning players who haven’t played in 6 months, or try the game on your android or IOS devices. You might even run into me in one of your matches. Thanks again to them for supporting my content and to all of you for watching. Just want to give a quick shoutout to some of the people on the Tanks Encyclopedia discord server who helped me find some of the sources for this video as well as to Red Effect for his help in translating some of the information. As always shoutout to my conelyfans for helping support this content as well as all of you who have grabbed yourself some of my merch. If you liked this video you’ll probably like my previous episodes on the ZiS-30 or the Soviet modifications of captured German tanks into self propelled guns. Hope to see you there or in my next video.