MG 120 (r) – The light machine gun – Russian model Degtjarjow DP 28

Written by Helmut Bindl on 02 October 2011.

The light machine gun Degtjarjow DP 28 was introduced to the Soviet army in 1928. It fires from an open bolt and is locked by a rising bolt lock. Feeding is conducted from a pan with 47 cartridges of the calibre 7.62 x 54R (7.62 Nagant). Its mode of fire is in sustained fire only. Variants to be mounted in aircrafts and armoured fighting vehicles with an improved magazine capacity of 63 cartridges were introduced as of 1930. The variants for armoured fighting vehicles could be modified so as to be suitable for infantry operations.

These weapons were captured during WW II and the German Wehrmacht used them with their original calibre and in a modified form to match German ammunition. The number of captured weapons was high enough for a respective regulation to be passed for them, as was the case for other Russian weapons.

Regulation D 50/2 "Information sheets about foreign equipment" ("Kennblaetter fremden Geraets"), edition 2, machine guns, gives us the first proof:

Unfortunately, this regulation does not say anything about the marking of such weapons as captured by Germany. This also confirms the assumption that there was no standard for marking captured weapons as German property during the period from 1939 to 1945. The weapons which were modified to match German ammunition are an exception. The following instructions can be read in the journal of army engineering ordinances ("Heerestechnisches Verordnungsblatt") from 1944.

Two of these modified weapons are on display at the WTS. Different methods were used to retrofit them to match the German calibre 8x57 IS. For this reason, they are true curiosities. As opposed to the captured weapons which were used with their original calibres, these two weapons bear the clear mark according to the ordinance. Official instructions as to which components had to be modified or renewed have not come to our knowledge so far. However, the modifications can be reconstructed on the basis of the two available weapons in the extent to which they can be seen from the outside. So it can be determined that there were at least two different methods of adaptation. Due to the retrofitting, the details of which are different with each individual weapon, one can assume that one of the weapons was modified at an armourer's shop right behind the front line, whereas the other one was retrofitted at a factory so as to fit German cartridges.

The barrel, breech and magazine had to be modified. As the ballistics of German cartridges is similar to that of the Russian ones, the sights did not have to be adapted. The major ammunition differences are the length of the casings and, thus, the overall length as well as the larger cartridge base of the Russian rim cartridge. These differences made modifications of the breechface and the extractor in the breechblock necessary. The barrel and the chamber had to be adapted to the German cartridges. It was also possible to modify the pan so as to match the cartridge which was longer by almost five millimetres. It is probable that such modified magazines were labelled "SS". Unfortunately, no matching magazines exist any longer for the two weapons.

Description of the weapons
Even the first assessment of its state makes it clear that this machine gun had been in use. All existing components of the weapon are marked with the same number. The magazine and the bipod are missing.

The person who retrofitted this weapon did not adhere to the instructions in detail when labelling it; the two engraving stamps for marking the weapons differ in size. Maybe they thought of the designation "heavy spitzer bullet".

The modification of the breechface at the bolt head took place by means of removing approx. 2 mm of the cartridge base diameter of the German cartridge. A new extractor with a longer extractor claw was installed. The modifications are clearly visible in the two pictures.

Modified breechblock

Original breechblock

The most complex modification is that of the chamber. Here, a special method was used with this weapon. In order to be able to use the numerous existing barrels, the existing chamber was drilled out and a new chamber suitable for the cartridge "S" was inserted. Due to a lack of time and personnel, it has not yet been possible for us to examine to which extent the transition cone and the groove and land profiles were adapted. It must be assumed, however, that the transition cone was prolonged in order to make it easier for the bullet to deform in the narrow barrel. A similar approach was taken in Austria during World War I when captured Mosin-Nagant rifles were adapted to fit the Austrian cartridge M 93.

It is true that this kind of use resulted in considerably more wear of the barrel but otherwise the adaptation of the weapons could only have taken place in the relevant weapon factories as the weapon workshops right behind the front line did certainly not have workbenches for the fitting of new barrels at their disposal.

Modified barrel

Original barrel

Note the last turn of the thread in this picture.

After this weapon was modified, proof tests were carried out according to regulations and one proof mark each was applied to the barrel and the casing.

The other MG 120 (r) was modified at a factory and received a new barrel in the calibre 8 x 57 IS. This barrel has the manufacturer's code "dfb" and, below that, "cz". The code "dfb" represents the Gustloff factory in Suhl, Germany. The meaning of the code "cz" has not yet been clarified. The barrel and the casing show neither a WaA gun acceptance stamp nor a proof mark.

The new barrel and view into the chamber:

The entire weapon was reworked and oxidised anew, but it probably did not go back to the front line. In this case, the marking corresponds to the regulations in the ordinance.

The breechblock lacks the extractor. It may have broken off during an attempt to load a Nagant cartridge.

The shape of the feeding device of the pan had to be modified so as to fit the longer German cartridges. Here you can see an unmodified original magazine without cartridges. The feeding mechanism which is shaped like a round can be seen here.