PE top mount model 1931 sniper rifles
The Model 1931 sniper rifle, or sniper rifle with the model 1931 scope and Smirnskiy mount (A. Smirnskiy was the designer of this mount) became the first sniper rifle that was officially accepted into service in the Red Army.
It was only produced in 1932-1938 by the Tula arms factory (serial production, trial models were produced in 1929-1931). Bases and mounts were also only produced by the Tula factory.
Model 1931 Smirnskiy top mount with model 1931 PE rifle scope.
Photo courtesy of Anton Patrakov.
The mount and scope were adopted in 1931, serial production started in 1932. The mount that was accepted into service in 1931 was a two-piece mount, it had a base (with a dovetail on the top) that was attached to the receiver with 6 screws, and a detachable mount, which was attached to the base's dovetail and locked with two thumb screws.
This was the third modification of Smirnskiy mount, which had many differences compared to the pre-serial mounts.
The first pattern Smirnskiy mount was designed in 1929 and had no separate base, it was attached to a dovetail welded to the top of the receiver. The second pattern of the mount had no base/dovetail at all, it had a wide bottom and was attached to the receiver directly with two screws from each side. Pictures and drawings of these mounts are available in the "Model 1891/1930 Rifle and its variations" book.
Book pages, showing early Smirnskiy mount designs
As mentioned on the general sniper rifles page, during the initial production period sniper scopes and mounts were installed on regular rifles with the best accuracy - best performing rifles were selected after test shooting, updated with a bent bolt, sometimes with walnut stocks.
Walnut stocks were used because they were much more stable in field conditions compared to birch stocks. The problem was that the Soviets did not have enough walnut blanks. Even though all snipers were supposed to have walnut stocks, due to this issue the majority of them were issued with birch stocks.
Smirnsky top mounts and bases were individually adjusted to each specific rifle, each mount was matched to the base. Holes for the base screws in the receiver were drilled through the base when it was attached to the rifle. Screw holes were blind, M5*0.5 threading was used. Hex receiver base screws were flat from the bottom, round receiver bases screws were conical shaped from the bottom. Base production tolerances allowed for a 0.5 mm (0.02") difference in the placement of the base holes, bases from one receiver did not always line up perfectly with another receiver.
After the base was attached to the receiver with screws, the mount with a factory zeroed scope was installed on it, the straightness of the setup was checked with a special optical device. The mount design does not allow side or vertical adjustments, so in cases where some corrections were required, it was allowed to grind the mount rings from the internal side (angle the scope) and mount wedge. Grinding of the mount base dovetail was prohibited, grinding of the internal part where it was attached to the receiver - allowed. All these modifications were allowed during installation of the mount and base at the factory only, any modification of mount and base in field conditions was strictly prohibited.
After the mount was matched to the rifle, the mount base, mount and receiver (hex pattern) were stamped with the mount assembly number. Location of the assembly number was different in different periods.
Pattern 1 (hex) : Earliest 1931-1932 receivers and mounts/bases were not stamped with assembly numbers at all.
Pattern 2 (hex) : Considering that there are very few known 1932 top mount snipers, it is very difficult to say for sure. Judging from existing rifles, since 1932 and up to the 1933, the assembly number was stamped on the right side of the receiver tang.
Pattern 3 (hex) : Since late 1933 or early 1934 up to 1936, assembly number stamping was made on the right front part of the receiver (hexagonal part) and bottom of the receiver recoil lug.
Pattern 4 (hex) : 1936 hex receiver snipers had the assembly number only on the right front part of the receiver (hexagonal part).
Pattern 5 (round): In 1936 production was switched to round receivers, assembly numbers were not stamped on the round receivers, only mounts and bases had them. Receiver was stamped with a "C" proofmark on top.
Since 1934 barrels were stamped with a "СП" sniper grade barrel marking (early 1934 snipers missed it). The marking was stamped after the barrel was attached to the receiver, at the same stage when the factory logo and production year was stamped. The action was blued after these markings were added, so they should be under the bluing. Serial number was stamped at a later stage, so a non-refurbished sniper rifle, like any other non-refurbished rifle, should have the serial number stamped over the bluing.
Action from an early pattern PE sniper (deactivated). 1933 date on the barrel is restamped with a 1934 date (receiver is 1933 dated), no "СП" sniper grade barrel marking. Receiver has mount assembly number only in the tang area.
Photo courtesy of Alexey "Jakes".
Mount assembly number in the tang area (C or O 1526)
Partially factory matching mod. 1931 Smirnskiy top mount sniper rifle (except mount). Mount and scope are from another rifle.
Photos courtesy of Georg Oberaigner.
Base is stamped with assembly number "Л525", mount with - "П575", which indicates that mount is from another rifle.
Receiver recoil lug is stamped with assembly number "Л525", mount base, which idicates receiver and base are original matching.
1934 PE top mount sniper, rougly converted to ex-sniper configuration by Arsenal No. 7 after 1945.
Photos courtesy of José Aguilera.
Receiver recoil lug and the hex part of the receiver are stamped with assembly number "П367". "Ь943" number on the receiver bottom is a steel lot number.
Because of the start of round receiver production the mount base was redesigned to fit the round receiver. Production of the new base type started in 1936. However, it was not the only change. The "Round receiver top mount sniper rifle" drawings were the first drawings that contained all non-standard (compared to regular rifles) parts of the sniper rifle, allowed tolerances during assembly, lists of metal compositions and metal blanks sizes, and were optimized for mass production. Earlier drawings existed only for the top mount, requirements for sniper rifles itself were present in a number of internal factory documents. The existing group of documents and drawings at that point was not optimized for mass production and was updated during general rebuild and optimization of production capacities in 1935-1936.
Mounts and bases from the different production periods also had some differences in construction, they are shown in the images below. The difference which is not shown in the image is the size of the mount screws (two big screws that were used for the attachment of the mount to the base). Early 1932-1933 mounts had screws with a 17 mm top part and diamond shaped knurling, later screws - with a 12 mm top part and vertical knurling. So far none of these mounts are known in private collections, pictures of the mounts in museum collections are not allowed to be posted online. However, an image of such a mount is present in the "Model 1891/1930 Rifle and its variations" book.
1932 - to early 1937 top mount snipers were issued with PE scopes, 1937-1938 top mount snipers - with PEM scopes. It is interesting that some of the earliest top mount snipers from the very early 1932 production were issued with Emil Busch Visar 5 scopes, approximately 100 of them were ordered in 1930.
These days many top mount snipers can be found in ex-sniper configuration, with bases removed and screw holes plugged and welded during postwar refurbishment. More details about this type are provided here.