In 1925 A.A. Smirnskii had already designed a small bore rifle designed on the basis of the Model 1891 7.62mm service rifle. This rifle received the designation “small bore rifle Smirnskii first model”. At the order of the Osoviakhim in 1926 A.A. Smirnskii also designed a conversion of the standard service revolver to shoot 5.6 mm (.22) caliber rimfire cartridges for training purposes.
This new training revolver, as originally constructed, differed from the standard service revolver in the following aspects: it had a single action trigger mechanism, reduced height of the front sight (to accommodate the ballistic characteristics of the 5.6 mm cartridge), inserts in the cylinder chambers for the smaller dimensions of 26 mm rim fire cartridge, a new .22 caliber barrel and changes to the breech block and firing pin to allow the use of the rim fire ignition system of the cartridge. Additionally the very first test models didn’t have the mechanism to move the cylinder forward, but gas leakage was excessive and the conversion process was simpler with the gas seal mechanism in place.
The conversion of these original small bore revolvers was carried out at Army arsenals and the shops of the Osoviakhim who used revolvers of earlier production, usually Imperial Russian production.
The conversion process was moved to the Tula Weapons Factory in the late 1920’s to enable mass conversions of service revolvers to the small bore version. In 1930 alone more than 2000 Nagant Smirnskii conversion revolvers were produced at the factory. Production/conversion is reported to have continued into 1939 when production needs for the Winter War terminated production, however, a 1940 dated factory revolver has been observed.
The factory conversions were carried out by replacing the following parts with purpose manufactured components designed for use in the small bore revolver; barrel, front sight, cylinder, breech block, and firing pin. It should be noted specifically the cylinder and barrel are NOT relined, but were new manufactured as .22 caliber parts.
When these converted small bore revolvers are fired, the cylinder advances to the barrel stub, just like a service revolver. The barrel stub fits into a counter bore on the face of the cylinder which helps to center the chamber of the cylinder with the barrel bore. The shorter.22 caliber cartridge does not extend forward out of the cylinder to create a gas seal so there is some leakage of powder gasses at the gap between the barrel and cylinder face. To aid in accuracy the trigger pull of the new small bore revolver was reduced to 1.5kg in single action fire. These early conversion Nagant Smirnskii revolvers achieved a good reputation for accuracy at a distance of 25 meters.
All of the factory conversions and dated factory conversions seem to be marked with a new Acceptance Commission mark on the right side of the frame and this new AC mark should be consistent with the year of conversion.
The last variety is the 7.62 caliber revolvers converted to .22 by gunsmiths. These consist of revolvers with original 7.62 caliber cylinders and barrels relined to 5.6mm. There is huge variety in how these were made and some are accurate and some are not.
As previously stated factory conversions were made by replacing 7.62mm parts with new, purpose made 5.6 mm parts – not converted 7.62 mm parts. However, most observed early examples are literally parts guns. The sideplates are more often than not replaced and renumbered and new parts substituted for worn parts. The factory seems to have taken great care to build these revolvers as they would see harder service than was common for the standard service revolvers.
In the case of the early dated and undated variations an earlier production, usually Imperial, revolver would be stripped to the frame and the new 5.6 mm barrel, front sight, cylinder, breech block and firing pin would always be used. The triggers seem to have almost always been replaced as well and are star marked, even on rare single action examples with Imperial hammers. The trigger and hammer sears were worked over to give them a 1.5 kg pull.
The revolvers were refinished nicely, not with a belt sander like later arsenal refurbs. The front face of the 5.6 mm cylinder was then given a “conversion” number and this number was also stamped on the right side of the frame. On the dated versions, both early and late, the year of conversion was also stamped next to the conversion number. The frame was given a new Acceptance Commission mark corresponding to the year of conversion. It is difficult to be sure, but it would appear that the grips were commonly replaced. Checkering pitch is around 1.5mm and some grip plates are virtually new.
Note that it is also common the see replaced hammers caused by damage from extended use. Training and target revolvers saw much more use than standard service revolvers and the Nagant firing pin/hammer assembly is a weak point in the design. With heavy use the hammer tends to crack and break through the hole for the striker/firing pin retainer pin. Pre 1937 hammers have the ‘V’ shaped checkering pattern on the spur and can be differentiated from the later version with their straight checkered spur. Replaced hammers on pre 1937 revolvers can be identified by this difference.
The basic trigger and cylinder advance mechanism is still present and unaltered in the .22 caliber Smirnskii revolvers. When the cylinder advances, the small diameter counter bore on the face of the cylinder mates to the taper of the barrel stub and insures good alignment of the chamber and barrel. It is NOT intended as a gas seal mechanism!
The breech block has to guide the firing pin to the rim of the cartridge rather than the center as occurs on the normal center fire service cartridge.
The front sights on the factory conversions are of the older Belgian design with a square notch on the rear of a truncated arch type sight, i.e. it isn’t simply a half moon sight that has been notched. Similar to the Belgian sight it has a pyramidal cross section and this shape was not changed with the 1932 sight change.
Even though testing had shown that the 1932 sight gave a better sight picture the .22 caliber front sights retained the same pyramidal section as the original Belgian sight.
The dated and undated early conversion seem to retain the ‘V’ shaped rear sight groove even though most were made after the sight change of 1932.
The tooth on the frame that originally mated up to the notch in the loading gate seems to have been always been removed from early frames at conversion if done at the factory (change of 1928). The loading gates are sometimes, but not always, replaced with star marked pieces without the mating notch.
The early undated factory conversions were the first model to be converted at the Tula factory from earlier standard service model revolvers by replacing the necessary 7.62mm parts with purpose built 5.6 mm parts. All of the early undated factory conversion revolvers observed have been altered from Imperial revolvers and the earliest was converted in the late 1920s. The cylinders and barrels used in these were not sleeved like the earlier Osoaviakhim modified revolvers, but used purpose made factory new components. The front sight was of the Belgian type with the notched truncated arch shape, but with a shorter vertical profile due to the ballistics of the .22 caliber round. The rear sight is still the ‘V’ shape used on the pre 1932 Service revolvers, even on revolvers converted after 1932. The firing pin and breech block were replaced with pieces modified to facilitate the use of rim fire ammunition. The trigger pull was reduced to 1.5 kg for better accuracy.
The early factory conversion revolvers are found in single action only as well as double action, but by far the majority of observed examples are double action. When found the single action only version is usually made with an Imperial single action hammer, not a Soviet hammer from current production modified by simply omitting the double action fly and spring.
Shown below is an early factory conversion from 1932 or early 1933. This revolver has the Tula commercial mark on the side plate. The cylinder is serial numbered with its own number and that number is put on the right frame in front of frame in the area where the OTK mark and accuracy proof are usually found.
The second type of Tula factory conversion has a date as well as a conversion number on the right side of the frame. These revolvers are still usually converted from Imperial revolvers. The new cylinder is given a conversion number and that number is stamped on the right side of the frame along with the conversion date. The earliest dates observed are 1933. Observed 1933 dated conversions are dated with a 2 digit date on the right side of the frame and sometimes a 4 digit date on the left side of the frame. 1934 and 1935 dated conversions are dated on the right side of the frame with a full 4 digit date. 1936 and 1937 dated versions seem to have reverted back to 2 digit dates. The later dated revolvers of this type seem to have better finish (blue and polish) than the early ones. A 1937 dated conversion of this type has been observed.
I’m going to show several different examples just to show the variations observed in these. There seems to be no hard and fast rules as to what types of parts were used. Note: the marks on the hammer, trigger guard, etc. are used to determine when the parts were made.
This revolver was converted from a 1917 dated revolver. This particular revolver still has a matching sideplate, but the numbering on the frame is suspect and might not be original. Original parts include only the trigger guard, frame and loading gate? (the loading gate is still a hammer marked notched piece but doesn’t seem to have the corrosion or polishing found on the rest of the revolver).
It would appear that this piece saw heavy use both before and after its conversion. The frame has been polished down removing most of the original marks and there is still some pitting seen on the rear sight hump. The hammer is a post 1936 replacement with the flat front checkering pattern. It would appear that the original conversion was as a single action – the star marked (!!) hammer block is still the single action version (when the hammer was replaced, they simply didn’t bother to change the hammer block?).
The mainspring is the lighter star marked type observed on the 5.6 mm revolvers and the rear sight has been modified to a square shaped notch a long time ago, but after the conversion refinish. It has been give a new AC mark with an added letter ‘Р’, probably for repaired in Russian (Ремонтировать is to repair or rework). This could have been from the hammer replacement?