Prior to World War One, the motorcycle was starting to be seen as a viable replacement for bicycles. The Germans were the first to introduce the motorcycle into military service in 1904 and by 1914, both the British and the United States also had motorcycles as part of their military forces. Not surprisingly, the usage of motorcycles continued through the post-WW1 years and when World War Two began, all of the major warring powers utilized motorcycles of various makes. Motorcycles were used by couriers, messengers, and as transports for men and matériel but the largest use of motorcycles was by scouts conducting reconnaissance operations. Not too surprisingly, sidecars were often attached to motorcycles. This permitted the motorcycle to carry a passenger, cargo, and in some cases, used to carry wounded away from the front line. As a vehicle used by the military, sidecar equipped motorcycles were soon fitted with weapons, even as far back as World War One. German Zündapp KS 600 and BMW R12 motorcycles with their sidecars fitted with Maschinengewehr 34 machine-guns are a common image in many books on World War Two. There were attempts to equip sidecars with heavier weapons and perhaps the Russians can take the grand prize for the largest gun ever fitted to a motorcycle/sidecar combination.
Prior to the 1930s, the Soviet Union did not have much in the way of indigenous motorcycles and relied heavily on imports. In fact, during World War One and into the Russian Civil War, the major brands of motorcycles in use by the Russian military were Indian and Harley-Davidson. By the mid-1930s, the Soviets were well on the path to producing their own motorcycles such as the TIZ-AM-600 (a copy of the British BSA Sloper 600), the PMZ-A-750, and the Dnepr M-72 (copy of the BMW R71). Still, Harley-Davidson motorcycles continued to see use and during World War Two, the Soviets received over 30,000 Harley-Davidson WLA motorcycles via Lend-Lease. So, a Harley-Davidson motorcycle was selected for the testing of a sidecar mounted ChK-M1 37mm anti-tank gun as a means of moving the gun around the battlefield. As a side note, the gun was also fitted to Lend-Lease Willys MB Jeeps and the GAZ-67 (the Soviet equivalent to the Jeep) among other transports.
The ChK-M1 was the final result of development of the ChKSh-1 which appeared in prototype form in the summer of 1941. The intent was to produce a anti-tank gun that could be airdropped and provide airborne troops with some capability to tackle enemy armor. Testing showed that the gun was flawed. It was deemed overly complex, had a slow rate of fire (between 8 to 10 rounds per minute), was inaccurate, and the armor penetration of the 37mm round was found wanting. In 1942, the Soviets set up a special design bureau, OKBL-46, to continue development of the ChKSh-1 and two designs emerged, the ChK-M1 and the ZIV-2. Between April 18, 1943 and May 28, 1943, both guns were put to the test but it was the ZIV-2 that came out the loser and the ChK-M1 was ordered into production on June 14, 1944. The first examples started to enter service in July 1944 and production continued through June 1945 with some 472 guns being produced.
The ChK-M1 had several features designed to both lighten the weight (in keeping with the need to be airdropped) and limit both size and recoil. The gun barrel was surrounded by a cylindrical shroud and within the shroud was a inert mass and a recoil spring. When the gun was fired, the barrel recoiled a maximum of 3.9 inches and the inert mass disengaged from the barrel, moving backwards 3.5 feet, compressing the recoil spring which then moved the gun back into battery. The entire gun, excluding the muzzle brake, was 7.6 feet long. The muzzle brake also added to the reduction of the rearward recoil. A good crew was able to put 15 to 25 rounds through the gun. The ChK-M1 fired the BR-167 armor-piercing round which weighed 1.7 pounds (7 ounces being the charge weight) and the penetration was approximately 20mm at a 60 degree slope and 25mm at a 90 degree angle from 500 meters. The other round the ChK-M1 fired was a high-explosive round, the OR-167. The 1.6 pound round had a 7 ounce explosive warhead fitted with a MG-8 fuze.
Some question if the ChK-M1 was actually able to be fired from the sidecar. The answer to that is that yes, it could, if the crew had no option to dismount the gun. The photograph makes it appear as if the gunner is resting the breech on his shoulder but he is not. When the gun recoiled, the breech would move to the right of the gunner's shoulder. The man seated behind the driver was the loader and both he and the driver carried ammunition in backpacks so in action, he would pull rounds from the driver's pack to hand to the gunner or load the gun himself. The ChK-M1 was fired via a trigger, which can be seen in the gunner's right hand. His left hand was used to effect traverse and what little elevation and depression the gun had via a vertical grip offset to the left of the breech. The far more normal operation of the ChK-M1 was for the crew to dismount it from the motorcycle, assemble the carriage, and deploy it in the ground role. A skilled crew could do this in 80 seconds. To that end, behind the loader were the simple, all-metal spoked wheels and carriage legs while the gun shield can be seen secured to the side of the sidecar. The gun shield was not large and had a meager 4.5mm of armor thickness which was, at best, proof against some small arms and fragments. The gunner was provided with a periscopic sight which allowed him to keep his head low and behind the gun shield. The entire gun carriage was very low and provided only 5 degrees of elevation and at most, 5 degrees of depression. The carriage also provided 45 total degrees of traverse. The low profile of the weapon usually forced the crew to operate the gun from the sitting or prone position. A typical ChK-M1 team consisted of six men and two motorcycles. The motorcycle shown here included the driver, gunner, and loader while the second motorcycle was manned by the driver, the gun team commander, and a ammunition bearer.
The ChK-M1 had a total weight of 478 pounds and it could be carried easily within the two major Russian airborne troop gliders; the Antonov A-7 and Gribovsky G-11. It could also be carried by the Lisunov Li-2 (the Soviet copy of the Douglas DC-3). The gun was usually airdropped via parachute from the Ilyushin Il-4 but the Li-2 was also used for airdrops as well. The sole user of the ChK-M1 was the 98th. Guards Infantry Division, its personnel from the 13th. Guards Airborne Division that had been formed on December 20, 1943. On January 19, 1944, the unit was included within the 37th. Guards Airborne Corps until reorganized again December 18, 1944 to the 103rd. Guards Rifle Division. The unit never saw combat during World War Two. On June 7, 1946, the unit became the 103rd. Guards Airborne Division and reformed on October 15, 1948 after absorbing several other units. Finally, on April 25, 1955, the unit was disbanded. It was likely just as well that the division did not see action as the ChK-M1 was not well liked in service. It was found that the barrel rapidly wore out while the accuracy of the BR-167 round dropped off quickly. In addition, the penetration value of the round was, by 1944 and into the early post-war period woefully inadequate in comparison to the later war Soviet 45mm anti-tank guns (such as the 45mm M-42). Finally, crews complained that the simple sight of the ChK-M1 suffered in low-light conditions, something that also plagued the 45mm guns but rather than improve the ChK-M1, the 45mm guns were recommended to be improved upon rather than a light gun that had little value.
