The Belgian contract terminated after the final delivery of the 20,000 contract revolvers in late 1898. The Russians, with the aid of the Nagant supplied advisors and tooling, started production at the Tula Weapons Factory in 1898 (this has been recently confirmed with a picture of an 1898 dated cutaway from the Tula museum and a deactivated revolver in the 14,000 serial number range from a collection).
During the process of “tooling up” for production, the Russians determined that the L. Nagant factory manufactured version of the pistol was too expensive and time consuming to manufacture, so they simplified the design and went about making manufacturing changes to cut costs and speed the production process. The first thing eliminated was the serial numbers on the non major parts of the revolver. The only parts that would be numbered were the frame, the side plate, the cylinder and the trigger guard. The serial number on the trigger guard would be eliminated during the First World War (mid production of 1916). The method of connecting the side plate at the base of the butt and the internal shape of the butt itself was changed. The method of retaining the lanyard ring screw was changed from a set screw to a pressed pin. The front sight shape was changed from the original notched model to a simple half moon. There was a change to the shape of the double action hammer block to be more like the single action (this was changed back to the original Liege design in 1899), and finally, the grip plates were altered by reducing the checkering on the grip plates from approximately 1.25mm or 20 lines per inch to about 18 lines per inch and the threaded grip plate retainer inserts were also simplified to do away with the lobe which prevented rotation of the insert in the grip plate.
The Belgian Contract revolvers have two keys projecting from the bottom of the side plate that fit into two matching recesses on the bottom of the butt of the frame as well as a projection that carries the lanyard ring. The lanyard ring carrier is threaded into the butt projection secured in place with a set screw. The butt plate is made of two pieces, a partial plate and the lanyard ring carrier projection on the frame side and the balance of the plate on the sideplate side.
The Tula manufactured revolvers have a simplified design. The butt of the frame is machined so that the butt plate is made of only one piece and the side plate attaches above the butt plate. Like the Liege manufactured design the lanyard ring carrier is threaded into the butt plate, but instead of requiring a set screw, the threaded carrier is locked in place with a pressed pin. The stub of the pressed pin acts as a locator for the side plate.
An additional benefit of this design is that the side plate of the Russian design is constant thickness and can be made from a simple plate of metal. The Belgian design has the keys and part of the butt plate protruding from it which require a thicker piece of metal and more machining.
The details below show the differences in the frame and side plate attachment between the Liege and the Tula manufactured revolvers.
=>Insert pictures of side plates here
The grip plates were altered by reducing the checkering from approximately 1.25mm or 20 lines per inch to about 18 lines per inch. It is almost not obvious unless you have examples to compare side by side.
The grip plates are held on with scews coming from the inside of the frame and sideplate into threaded inserts which are pressed into the wood of the plates. On the original Liege manufactured Russian contract revolvers these threaded inserts had a "lobe" on them to keep them from rotating in the wood of the grip plates. On the Russian production the threaded grip plate inserts simply knurled to do away with the lobe. This would have been a significant reduction in machining time on a small part!
The front sight of the Liege manufactured revolvers has a notch cut into its back giving it a vertical face on the rear side of the blade. The Russians used a simple half moon design thinking that it would do less damage to the holster and be cheaper to manufacture. The half moon sight remained standard on the service revolver until mid 1932.
Another change that occurred in this period was the simplification of hammer block for the double action or Officer’s model revolver. The single action revolver used a hammer block that was identical to the original Belgian produced military contract design. This remained essentially unchanged, except for the way it was marked until termination of single action production in 1922.
The original design of the firing mechanism on most Nagant manufactured revolvers was double action. However, the Imperial Russians didn’t want a double action for the reasons explained in the development chapter. So Nagant came up with a unique solution only altering a minimum number of parts. The difference between a double and single action is only really 2 parts, the hammer assembly and the hammer block or slider. The gas seal Nagant revolver can be change from single action to double action with no more tools than a screw driver in literally less than 3 minutes!
There is a projection that forms a hook on the front of the single action hammer that prevents the upward movement of the hammer block when the trigger is pulled. There has to be a corresponding clearance in the hammer block to permit the hammer to fall far enough to allow the firing pin to strike the cartridge with the block in its upward position.
=> insert picture with block raised and SA hammer forward
Single action hammer and hammer block from a 1901 dated single action. Note the clearance cut in the lower rear face of the hammer block.
The double action revolver does not need this projection on the front face of the hammer as pulling the trigger allows the hammer to rotate back and fall to fire the shot. Since it doesn’t have the projection, it doesn’t need the clearance cut out on the hammer block. This version is what is found on the 1897 and later double action commercial gas seal revolvers manufactured at the L. Nagant factory in Liege.
In an effort to simplify production of the parts used on the original Tula manufactured revolvers, the Russians used almost the same hammer block on both the single and double action versions of the revolver, the only difference being the hook on the rear face. A single action hammer block could have the projection ground off for double action use. However, it is likely that this cutout created a weakness in the hammer block and the higher rate of fire in the double action version may have caused failures. This version of hammer block is seldom seen in surviving period examples.
The version of the hammer block found in the very early double action Tula revolvers still have this cutout as late as mid 1899. By 1900? the cut out had been removed and the hammer block design reverted back to the original Belgian commercial design. This design would be used until the end of production.
Detail of the hammer and block from an early 1899 dated revolver and from a 1901 dated revolver.
Detail showing the 3 early hammer blocks side view then ¾ view. Left to right: 1897 Nagant single action, 1899 Tula double action with cutout, 1901 Tula double action without cutout.
Front and rear views of the three different hammer blocks. Left to right: 1897 Nagant single action, 1899 Tula double action with cutout, 1901 Tula double action without cutout.
Note also the early location of the “circle T” OTK mark moving from the back face of the 1899 block to the front face by 1900.
There are several basic kinds of marks found on the Russian manufactured revolvers; an Arsenal mark denoting the factory and year of manufacture, serial numbers, an accuracy proof, and OTK marks. Most of these marks would remain fairly consistent through out Imperial production.
Early revolvers produced at Tula have the arsenal mark shown below. This style arsenal mark was in use from 1898 until late 1912. -Note that the Russian letters in this arsenal mark are in old, pre - 1917, characters.
Early Tula manufactured revolvers have the serial number in 4 places: on the left side of the frame in front of the cylinder, the inside of the sideplate, the front face of the cylinder and the left side of the trigger guard. Except for the removal of the serial number on the trigger guard in mid 1916, this would remain consistent throughout all Nagant production.
Shown below are examples of the serial numbers on the front face of the cylinder. The numbers are placed between the chambers followed by a small hammer OTK mark. The marks following the OTK mark are inspector marks and have no currently known meaning. If the serial was only 4 digits, the space following the inspector marks was left empty.
The Acceptance Commission (AC) mark on the Russian production revolvers from 1898 into 1909 consist of a Romanov double headed eagle holding the traditional scepter and orb under a crown. All over the Russian letters ‘ПК’. The letters are for Приемная Комиссия or Accepting Commission (PK in Latin letters).
The location of the AC mark on the 1898 to mid 1899 production revolvers is located in the same place as the Imperail Acceptance mark on the Liege manufactured revolvers, directly above the side plate retainer screw on the right side of the revolver. The detail below shows the location of the AC mark on the 1898-9 production revolvers.
More detail can be found in the AC marks pages
The accuracy proof on the early Tula manufactured revolvers is a circled ‘К’ on its face found on the lower front right side of the frame. A “lazy” circle ‘К’. The ‘К’ is for Кучность стрельбы or quality of shooting.
The Department of Technical Control put marks on various parts of the revolver to indicate that the parts were manufactured within proper tolerances. Since most parts of a Nagant revolver are interchangeable from the original revolvers delivered from Liege in 1896 to the end of production after World War II, this was a significant accomplishment.
Different arsenals used different OTK marks at different periods; Tula used a hammer until 1928 - then a simple 5 pointed star, Izhevsk used a bow and arrow and then later an arrow within a triangle, and Sestroretsk used a simple arrow.
OTK marks differ from inspectors marks, usually found within the revolver.
The OTK marks found on the first Russian production revolvers are of three types; a hammer without a circle, a very small hammer within a circle and a larger hammer within a circle.
The first mark, the hammer without a circle, is found on the frame (right side in front of the cylinder), on the barrel (left side on the front of the front sight platform), on the ejector rod (forward left in locked position), the right side of the base of the front sight, the front face of the cylinder pin, the front face of the loading gate, the inside lug of the loading gate spring, the front face of the cylinder, the front left side of the trigger guard, the inside of the cylinder pawl, and the hammer fly of the officer’s model (left side). The details below show the locations of the uncircled hammer OTK marks.