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.

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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.