Receiver

The receiver was the most complicated part of the rifle. In general, during the whole M91/30 production period there were two main types receivers - the so called "hexagonal" type and "round". The change of the receiver shape from hex to round was not caused by the M91 modification in 1930. It happened because of the general production optimization in the early 1930's. Both types of receivers were made by milling, despite some sources stating that lathe works were used during round receiver production, this is not correct.


Both of these main types of receivers had some modifications, these were introduced into production after the main drawings were adopted, these changes were (included to them as additional list of changes*).

* List of changes is a document which includes changes that were introduced after adoption of the main drawings. It contain information about original size, new size and drawning of each change. So basicly set of drawings for each weapon model contained main drawings with few additional lists of changes.


The main goal of this page is to explain why some changes were introduced into construction and when this was done. You will not find a "list of receiver variations" because it is senseless - new features were introduced into production in a different periods, sometimes they overlapped with each other, sometimes not. This caused a huge number of possible combinations. In most cases, none of these features alone, or in combination with others, make a receiver "rare". They were a production norm at the time when these receivers were made.

Hexagonal receiver drawings

On the top - hex receiver, on the bottom - round receiver.

The first round receivers were submitted for trials in November 1933. A few rifles, which in addition to round receivers had several other trial features at that time (two-piece welded bolt body, new barrel bands (without button), magazine body with 4 piece front end and some other non-standard elements) were made by the Izhevsk factory.

 

After trials, it was recommended to introduce this new receiver into mass production. The round receiver was included in the drawings during their general update in 1935. Because Izhevsk was the factory which originally designed the round receiver, it started serial production in 1935, almost completely switching to the round pattern at this time. While 1935 shows mixed production of round and hex receivers for Izhevsk, 1936 was year when almost all receivers were already round, only few 1936 dated hex receivers are known.


Tula started round receiver production in 1936 (same year that the main drawings were officially adopted, which were created in 1935), and completely switched to round receivers during this year. Some 1937 Tula rifles can be found with hex receivers, so far all known examples of these have low serial numbers and the receivers are 1936 dated, they are made from leftover parts.


In 1938 the Izhevsk factory offered new modifications - few trial rifles with modified receivers were made for factory trials. Compared to regular receivers, these receivers had no inner receiver ring/feed ramp (which was required for correct feeding of the older, round nosed bullets), and through the front receiver screw hole in the receiver lag. Elimination of the inner receiver ring was necessary because of the supposed changes in receiver production technology - the factory planned to replace milling of the internal channel with broaching.

These modified receivers successfully passed factory trials, and then, proving ground trials. Afterwards, in 1939, it was suggested to produce 20,000 rifles with modified receivers for wider field trials, but so far exact quantity of ordered rifles is unknown. In 1939, all of the mentioned changes were included into the main drawings (as a part of a list of changes). Production of the through hole started immediately, while the elimination of the receiver ring and broached channel were introduced into the mass production only in late 1941 by the Izhevsk factory (small trial batches were also made in 1939-1940). Interestingly, even after the broached channel was introduced into production, only some of the receivers had broached channels, the majority still were milled. Both of technologies were used together.

On the left - receiver with feed ramp and milled channel, on the right - without the ramp and broached channel

On the left - receiver with broached channel, on the right - with milled channel.

View on the feed ramp on a cutaway receiver

Feed ramp on the scheme.

Drawing made by M.N.Fokin

On the top - receiver with a through front screw hole, on the bottom - with blind hole.

In the fall of 1941 the Izhevsk factory, which was the only manufacturer of M91/30 rifles and M38 carbines at that moment, implemented a big number of simplifications, which allowed to rapidly increase production numbers. Some of those changes were related to the receiver. One of the main changes (but not the most visible one) was the elimination of the stepped receiver tang. This caused a problem - receivers with non stepped tangs did not fit in earlier stocks with cutouts for stepped tangs. However, this issue was easy to fix by cutting some wood in the stock.


All receivers were issued with a "high" wall, which was previously observed only on sniper rifles made for the PEM sidemount, mod.1936, made by the Tula factory in 1938-1940. The "high" wall on the receiver added to its total weight, but saved time and tools that were previously spent on additional machining. The same thing happened with the rear of the receiver - its machining pattern was simplified compare to prewar rifles. A few machining patterns of the rear part of the receiver have been observed, but they are just production variations. Final polishing of receivers in late 1941-1943 was much lower compared to other periods, machining marks are visible. Usually these are called "rough wartime receivers".

 

Another thing that was eliminated during production simplification was extra notch in the stripper guide area. This notch was an obsolete feature, same as the inner receiver ring. It was necessary when the model 1891 rifle was accepted to service, but already useless in the 1940's. The notch was required because the Nagant stripper clip, which was adopted together with the model 1891 rifle, had a profile that required two notches. Already in the 1890's this stripper clip was updated, its profile was changed. This second notch was already unnecessary but it  remained in the drawings until the 1940's.

On the top - rough wartime receiver (Izhevsk production), on the bottom - prewar round receiver.

On the left - stepped receiver tang, on the right - non stepped receiver tang (wartime pattern).

On the left - stock with lugs for the stepped receiver, on the right - stock for the non stepped receiver.

Differences in the machining pattern. On the top - prewar pattern, on the bottom - one of the Izhevsk wartime patterns non-machined rear.

Extra stripper clip notch, required for the zero pattern stripper clip, created by Nagant.

Profile of the zero pattern stripper clip, created by Nagant.

Receiver without the extra stripper clip notch, wartime Izhevsk pattern

A different approach to receiver production during wartime years was used in Tula. As mentioned in the section about manufacturers and production numbers, prewar "Tula" and wartime "Tula" rifles were made by different factories. In October 1941 Tula factory #314, which made M91/30's up to the mid 1940, was evacuated to Mednogorsk, where it continued SVT-40 production. In January 1942 in the buildings of the evacuated factory #314 a new factory was created, #536. Since almost all equipment and workers were evacuated, this factory had huge problems with setting up of the production.

 

First rifles were produced the in February of 1942. Prewar drawings were used, so the earliest configurations of  receivers, made in Tula in 1942, were quite similar to the configuration that was produced in 1940. 1942 Tula receivers still had a stepped tang, extra stripper clip notch, no feed ramp and through hole. The only difference was that the receiver had a high wall on regular rifles, that was not used in 1940. In 1943 this factory stopped making the stepped tang, but the extra stripper clip notch was still being machined. The right rear part of the receiver was  fully machined, not semi machined like it was done in Izhevsk during the same period.

1943 Tula receiver without a stepped tang and a fully machined rear.

It should be mentioned that all receivers and barrel blanks were supplied to Tula from Izhevsk during all production period, where the factory which produced them was located. Considering that in 1942-1944 the Tula factory had huge problems with machinery and equipment, a big percent of the receivers used were supplied from Izhevsk not as regular blanks, they were already machined (in different stages). It is very common to find Izhevsk markings on the receiver tangs, which are restamped with Tula markings, or even left intact. There are even recorded cases of supplied barreled receivers, where the barrels were already marked with Izhevsk stamps, which were subsequently restamped with Tula markings.

 

Some 1942-1944 receivers that were used in Tula for rifle production can have Izhevsk markings, Izhevsk machining patterns, or both, and that's the norm. Generally, wartime Tula receivers, even if they had an Izhevsk machining pattern, had much better final polishing, almost similar to prewar. This was because Tula had much lower production plans, they tried to keep final polishing at the prewar level whenever possible.


According to one of the late 1944 reports, over 60% of receivers used by the Tula factory at that moment were recycled, that were taken from the damaged rifles (round or hex pattern). Use of recycled hex receivers is very obvious, but round recycled receivers are much more difficult to spot, and they were also widely used. Such a feature, atypical for 1942-1945 production, as a low-wall round receiver normally indicates that the receiver is from an earlier rifle.


Tula started to use recycled receivers in production starting in mid 1943. In the earliest stages hex receivers were even reworked to a round pattern, such receivers are known, but this was done for a very short period of time, shortly afterwards hex receivers were left intact. The percent of recycled receivers in production constantly increased, since early 1944 they were the majority. However, they were not used on sniper rifles. For 1944 Tula M38 or M44 carbines, a newly produced receiver is even more rare than a recycled one.


Use of recycled receivers was a common practice for Soviet factories. These receivers were widely used during the early and mid 1920's, limited use is also observed during the late 1920's and early 1930's. The only years when these receivers were not used are 1935-1940 and 1946-1948. In 1941 (after the beginning of the war) Izhevsk actively used recycled receivers in the production of regular rifles and barreled receivers, in 1942 their use was very limited but was still present, so far they have only been recorded on barreled receivers. Currently there are no recorded case of recycled receivers use by Izhevsk factory in 1943-1944. In 1945 they were used on a batch of M44 carbines, which is quite strange considering that production capacities in 1945 were much larger than the quantity of weapons that were actually produced. When factories used recycled receivers, they took serviceable receivers from damaged rifles. There was no system, any earlier year or manufacturer can be found.

1945 Izhevsk M44 carbine, produced with a recycled reciver. 

Photo courtesy of Robert Larkin

Since mid 1943 the Izhevsk factory started to improve final polishing quality, wartime simplifications in some aspects were rolled over. Late 1943 rifles and carbines already had much nicer receiver and barrel polishing  compared to earlier specimens. According to a 1943 report, one of the goals for the Izhevsk factory for 1944 production was a complete restoration of prewar production standards. It should be mentioned that the factory did not manage to complete it in 1944, it was done in late 1945. Some 1943 rifles shows that efforts were made. Below you can see an image of a late 1943 rifle with an 1943 Izhevsk wartime pattern receiver (no inner receiver ring, no stepped tang), but with a low wall. Low wall receivers returned into mass production only in early 1946.

Late 1943 Izhevsk rifle with 1943 produced low wall receiver.

Photo courtesy of Dave Phillips

On the top - lowwall postwar receiver, on the bottom - rough wartime round receiver. Both are Izhevsk production.

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