Evolution of the Danuvia sub-machineguns
Hungarian 39.M Danuvia submachine gun
Also known as the "Király-submachine gun" after the developer Pál Király, although other engineers also helped with the development. This is probably the best-known weapon of Hungary. Originally the weapon was ordered by the Hungarian Police and Gendarmerie. They wanted a submachine gun which looked like a carbine because such look gave more magistery to the wielders. The test weapon was finished on 14 November 1938, and it was recommended to the Hungarian Army too. The General Staff became interested and after the test shots they ordered the weapon for military use, meanwhile, they also wanted some minor modifications - decreasing the rate of fire to 750 rounds/min, bayonet fix for the 35.M bayonet. It was put into service as the 39.M submachine gun.
The Király-submachine gun used a delayed blowback, selective fire action which made it quite reliable and functioned well under subzero conditions on the Russian front. The fire selector/safety is the circular cap located on the rear of the receiver and is operated by rotating the cap to align with one of the three settings: 'E' for semiautomatic fire, 'S' for full automatic fire and 'Z' for safe setting. After a loaded magazine is inserted, a bolt handle is pulled back, the bolt stays in the rear position. After the trigger is pulled, a spring-loaded bolt moves forward, pushes a cartridge into the chamber, and the firing pin is released initiating the firing. Blowback gas starts the reloading process again. The weight of the heavy bolt carrier provides the necessary delay. At the single shot setting, the bolt stays in the rear position.
The weapon had a 40-round staggered row foldable/detachable box magazine. The magazine, even when loaded, can be folded forward into a recess in the stock, where a plate then slides over it. The folded in magazine was liked by the troops because enemy sniper spotters could not differentiate between regular rifles and machine guns from the distance. The weapon had a 500 mm carbine-length barrel to increase accuracy. It fired 9x25 mm Mauser cartridges with 450 m/s muzzle velocity. This also caused logistical problems because this was the only weapon on the front issued with this cartridge. The 39.M had a 760-780 rounds/min rate of fire.
Despite being an accurate, easy to maintain and use, reliable weapon it still had its flaws. Most of the problems were the non-heat treated magazines' lips wearing out too quick. Because of this, the loading/ejecting mechanism tended to jam sometimes and to avoid this the General Staff ordered the troops to load only 30 cartridges into the magazines instead of 40 which solved the problem for a time.
The production of the weapon could start only in 1942, and even in that year, the engineers had to look for other materials to produce the weapon because the best quality steel was used for aircraft and armored vehicle productions. Around 13322 39.M submachine guns were produced by the Danuvia company.
39/42.M Danuvia submachine gun: a less known variant of the original weapon which was developed in 1942. There were two main differences; the magazine was canted slightly forward when in the fixed position as opposed to the straight vertical position of the 39.M magazine, and because of that the ejector was moved from the receiver into the bolt carrier. This method solved the main problems of the 39.M and it would be right to call the 39/42.M the pre-production prototype of the 43.M Danuvia submachine gun. The exact number of built 39/42.M SMGs is not known, remaining documents mention only 6 but not one built model remained.
39/A.M Danuvia submachine gun:
The Hungarian paratroopers became interested in the weapon as well, but the original submachine gun was too long for them to use. The engineers modified the original weapon in which the paratroopers themselves helped quite a bit. The 39/A.M submachine gun got accepted in 1941 but the first weapons were produced in April 1943. The 39/A.M had a folding wooden butt which made it easier to handle. But even with that the weapon was not quite liked by the paratroopers they still waited for a more easier-to-handle submachine gun. The Hungarian Army considered issuing the weapon to the mountain troops and for tankers too. The exact number of produced 39/A.M submachine guns is not known.
Hungarian 43.M Danuvia submachine gun
In 1942 it became clear that the 39.M Danuvia submachine gun did not meat all the expectations of the Hungarian Army. The engineers developed the weapon and showed the blueprints to the General Staff on 11 February 1943. The new, lighter submachine gun was accepted and put into service as the 43.M Danuvia. The General Staff ordered the Danuvia factory not to stop the production of the 39.M and 39/A.M submachine guns but slowly retool to the 43.M, the FÉG company also joined into the production.
The 43.M is essentially the same as the 39.M, but with a folding metal stock. A pistol grip was added. The ejector was moved from the receiver into the bolt carrier but the weapon still used a delayed blowback, selective fire action. Wooden strips are installed on both sides of the metal frame/receiver. The weapon had a 40-round staggered row foldable/detachable box magazine. The magazine of the 43.M is canted slightly forward when in the fixed position as opposed to the straight vertical position of the 39.M magazine. The magazine, even when loaded, can be folded forward into a recess in the stock, where a plate then slides over it. The weapon had a 425 mm carbine-length barrel. It fired 9x25 mm Mauser cartridges with 425 m/s muzzle velocity. The 43.M had a 650-700 rounds/min rate of fire. The magazines and most other parts of the 39.M and 43.M are not interchangeable. The submachine gun still had a bayonet fix for the 35.M bayonet.
The production started by FÉG and Danuvia in Summer 1943 but there were serious problems, namely the lack of materials and proper tools. Because of that the first 43.M submachine guns were finished at the end of November 1943. Around 20000 43.M Danuvia were produced by Danuvia while FÉG probably did not finish any, FÉG produced parts and half-finished models mainly. The 43.M submachine guns were used by all branches of the Hungarian Armed Forces, even by paratroopers and mountain troops who finally got their light, easy to handle machine guns.
43/A.M Danuvia submachine gun
A less known variant. During the test of the 43.M in winter 1943 there were still some flaws, namely the 43.M was very sensitive to the flaws of the cartridges which were produced from materials with less quality at that time. Because of this the engineers developed a slightly different variant of the weapon. The 43/A.M used a blowback action instead of the well known delayed blowback. This made the production more easier because a blowback needed less parts than a delayed blowback, and it also solwed the flaws of the 43.M which were caused by the cartridges. It's easy to distinguish a 43.M from a 43/A.M; because of the blowback action the rear of the weapon became longer, it reached above the joints of the folding metal stock. The General Staff ordered both Danuvia and FÉG to slowly retool to the 43/A.M without stopping the production of the 43.M. They also ordered the troops to convert all 43.M submachine guns to 43/A.M with the parts they received which was an easy procedure and could be carried out on the field. To convert a 43.M to a 43/A.M all that had to be done is to shorten the spring from 23,5 spirals to 20, change the action from delayed blowback to blowback and to change the bottom. Converting the weapon did not caused changes in the specifications. Sadly no documents remained about how many 43.M submachine guns were converted into 43/A.M and no such weapon can be found in public nor private collections