The 1926 TK Korovin Pistol - Тульский Коровин

A First Model Korovin
A First Model 1926 TK Korovin Pistol

The 6.35 mm Korovin Pistol (Pistol TK)

Sergey Aleksandrovich Korovin
Сергей Александрович Коровин
Sergei Aleksandrovich Korovin

The Tula Korovin pistol or TK was designed by Sergey Aleksandrovich Korovin (1884-1946). He was born in Kharkov and after completing high school he attended the Kharkov Techinical Institute. He was expelled from the institute in 1905 for revolutionary activities. He then immigrated to Belgium and worked in the factory of John Moses Browning in Herstale near Liege. He rapidly gained experience in design and construction of firearms (already by 1912 he had designed and patented in Belgium an original self cocking firing mechanism).

In 1914 at the beginning of the First World War he returned to Russia and failed to obtain a weapons designers position at the Tula Arms Factory and worked at several plants in Petersburg during the war.

In 1920 Korovin did become a designer at the Tula Arms Factory (ТОЗ) and in 1920-21 designed his first self-loading pistol for the 7.65 mm Browning cartridge (.32 auto). On 29 May 1923 the Artillery committee, based on proving ground testing of several automatic pistols gave the following conclusion that:
"The pistol of Korovin’s system had advantages over other systems in terms of its constant readiness to fight and Safety. Functioning of its mechanisms, even in the dust, was reliable. The proving ground thinks this gun suitable for arming commanders".

However, the weight of the pistol was excessive (915g) and its complexity kept it from being accepted into service.

At the request of the sports group Dynamo (МПСО Динамо), supervised by the NKVD, Korovin designed a variation of his pistol for the internationally popular 6.35x15 mm Browning cartridge (.25 auto). By mid 1926 Korovin had completed his design, and production started at the Tula Weapons Factory in late 1926. In 1927 the TK was officially approved for use as "TK pistol, model of 1926" (Пистолет ТК образца 1926 года). The TK pistol bears the distinction of being the first Soviet-made semiautomatic pistol and was produced until 1935.

The Tula Commercial Mark
The Tula Commercial mark

Since it was originally intended as a sporting/commercial pistol, which, in the Soviet Union of that period would mean a police and gendarmerie pistol, it is marked as a commercial weapon with the Tula “Triangle T” marking (commercially produced weapons were not sold to the average Soviet citizen). This commercial mark is also found on some .22 caliber Nagant revolvers and sporting rifles manufactured in the 1930’s.

Although never officially adopted into military service, it was used successfully in the late 1920s and 1930s as an officer’s pistol by commanders of the Red Army (RKKA), officials of the Communist party and Soviet government as well a presentation pieces for various achievements. The NKVD was also a major customer.

The official Russian name for this pistol is the TK for Tula – Korovin. Westerners have called it a “TOZ” or “TOЗ” because of the marks on the late version’s plastic grips (TOЗ stands for Тула Оружные Завод, or Tula Weapons Factory in Russian).

The TK is a blow back semi-automatic pistol. It is single action only and uses a striker mechanism similar to the 1910 and 1914 Mauser pocket pistols. The manual safety is located on the left side of the frame above the trigger. The magazine is single stack and is retained by a release located on the bottom, back of the grip. Early pistols usually have wooden grip plates retained by screws. Later models have black plastic grip plates with internal spring retainers similar to the TT 33 (Tula Tokarev) pistol. There is an illustration of an early model pistol with plastic grips retained by screws in Zhuk.

The TK pistol is a bit larger than one would expect to see in a 6.35mm pistol. This seems to have been intentional to give a bit more firepower to the weapon, both in velocity and magazine capacity. In comparison with the Browning 1906, the longer barrel is claimed to give an additional 28 m/second velocity (228 m/sec vs. 200 m/sec) and the magazine holds 8 rounds, an additional two rounds over the 1906 and most other 6.35 mm autos.

A Browning 1906 and a Korovin
For size comparison a Browning 1906 and a First Model TK Korovin

Russian/Soviet sources make the claim that while the TK was initially designed around standard 6.35mm Browning /.25ACP ammunition, its strength allowed Soviet arms makers to load a similar cartridge to somewhat higher energy levels (about 20 to 25% increase in muzzle energy and penetration) (source: A.B. Zhuk ,Pistols and Revolvers).

This increased power cartridge was called the 6.3mm Tula. Though this round is obviously based upon the .25 ACP round, it uses a slightly longer and heavier bullet along with a much greater powder charge. The round is close enough to the dimensions of the .25 ACP that one can still fire the .25 ACP from the TK without a problem, but the typical .25 ACP pistol is not designed to take the higher chamber pressures developed by the 6.3mm Tula round and a chamber or barrel explosion could result.

From the observed serial numbers on observed pistols it would appear that well over 500,000 of these pistols were produced. However, they are very seldom encountered in the west, which seems unusual considering the number produced. There has been very little interest in them and it is very unusual to see more than one of them at a time and this, to my knowledge, will be the first definition of the various models of the Tula Korovin pistol.

The First Model

Serial № 7906 First Model Korovin
Early First Model TK Korovin
From the Collection of Bob Adams

There are three sub variants of the First Model Korovin. The first is the early pistol with a squared front sight and safety dimple. The second is the ‘A’ Series which has the safety dimple and the later style half moon front sight. The last is the Late Model with the half moon sight and no safety dimple.

General Description of the First Model

The most noticeable feature of the First Model TK is the wooden grip plates retained by 2 screws, one on each side, holding the grip plates in place. These grip plates are completely covered with fine checkering. Under the grip plates the frame is milled with 2 scalloped out areas, probably originally intended to reduce weight. The milling pattern of the frame under the grips along with the screw retained grip plates is what defines the First Model Korovin. These pistols will be seen in the general serial number series up to about 210000. All observed ‘A’ Series guns are also all First Model.

The First Model Korovin is defined by the milling pattern of the frame. It has two scallop shaped cutouts milled out of the back side of the frame which was probably done to reduce the weight of the pistol. There is a threaded hole to facilitate the attachment of the wooden grip plates. Some early/transitional Second Model pistols still have the screw hole, but do not have the early milling pattern.

Serial № 209610 First Model Korovin
Serial № 209610 Detail of the frame milling on a First Model Korovin. The two “scallop” shape cutouts at the rear would be eliminated with the Second Model.

The slide of the First Model has two milled out areas at the rear of the slide to reduce weight and 14 vertical grooves. The rear sight has a wide base. The trigger is usually heavier (thicker) than in the later models. This slide design is common both First and Second Models.

Virtually all Korovins seem to have the Tula commercial ‘T’ in triangle mark on the left side of the frame. Serial numbers normally are found on the left side of the frame and slide and on the bottom of the barrel. On the right side of the pistol above the point where the trigger guard joins the frame is usually found a circle 'K' accuracy proof. Right below this on the trigger guard is usually found an inspectors mark (different marks have been observed here).

Serial № 75538 First Model Korovin slide
Serial № 75538 Detail of the milling on a First Model Slide. Note the normal serial number locations.
Serial № 75538 First Model Korovin slide
Top view of the First Model slide. First Models will not have the witness mark in front of the sight that is found on later Second Models.
Serial № 75538 First Model Korovin barrel
Location of the serial number on the bottom of the barrel
TUla Commercial Mark FIrst Model Accuracy Proof First Model
Left: Tula Commercial Mark found on the left side of the frame above the front of the trigger guard.
Right: Circled ‘К’ accuracy proof found on a First Model Korovin It is in the form of a circled ‘К’ usually on its face located above the front of the trigger guard on the right side of the frame. The ‘К’ is for Кучностъ or Quality in Russian.

It has been reported that the original grip plates had a diamond framing the retaining screw on both sides and later replacement plates were completely checkered. However, the majority of observed pistols are completely checkered and don’t seem to be replacement grips. The author has only observed 1 pistol with the diamond framing and the grips looked to have been worn and then checkering redone.

Factory wooden grip plates usually have an inspectors stamp on the inside of the grip plate and a brass insert to prevent grip plates from cracking.

Left grip plate with Diamond Pattern Normal pattern left grip plate
Left: A diamond pattern checkered grip plate. The diamond around the grip plate retaining screw is evident.
Right: A normal grip plate without the diamond pattern.
Note that both grip plates show the brass inserts around the grip plate retaining screws
Grip plates inside view=
Right: Inside of the grip plates from an Early First Model

Left: Outside view of the grip plates from a Late First Model. The brass inserts can be seen in the holes for the retaining screws
Right: Inside view of the same grip plates. . Note the inspector’s stamps
Illustration from A.B. Zhuk
No example of a First Model with plastic grips has been observed, but an illustration in A.B. Zhuk’s Pistols and Revolvers book shows such an example. The illustration shows a set of replacement plastic grips for a Late First Model pistol – notice the location of the screw! Some of the early Second Model guns still have screw retained grips but the frame is milled to accept the later Tokarev style grip plates.

Early First Model

On guns under approximately serial № 100000 the frame has a dimple to indicate the safe position of the safety. It is not a detent as the back of the safety lever is smooth. The Early First Model also has a squared front sight blade. Guns after about 100,000 have no safety dimple and a half moon round front sight blade. It is unknown exactly when this change was made - Serial № 92060 is an Early First Model, Serial № 135382 is a Late First Model.

Early First Model front sight Early First Model Safety
Left: Squared front sight blade found only on the Early First Model
Right: Early style safety with dimple
Early First Model Early First Model
A typical Early First Model
Serial № 7903 (Bob Adams Collection)

One early First Model pistol (Serial № 23412) has been observed with the serial numbers on the right side of the frame and the front of the front face of the slide. It also has a shinier type of blued finish than other pistols observed from the period. There is an extra mark beside the Tula Commercial mark. The reason for the differences in this pistol are unknown.

Unusual Early First Model Unusual Early First Model
Serial № 23412 Early First Model. There is no serial number visible from the left side. The frame number is located on the right side above the trigger.
Unusual Early First Model Unusual Early First Model
Serial № 23412 Early First Model.
Right: Slide Serial № on the front face under the barrel
Left: '3' in a box mark by the Tula Commercial Mark

Late First Model

Late First Model guns differ from the early first model in only the shape of the front sight and the lack of safety indicator dimple. The front sight shape change was probably done to make the pistol easier to get in and out of a pocket without catching. Late First Models still have the characteristic frame milling for the wooden grip plates. Serial № 209610 is the highest numbered First Model observed. Serial № 211986 is a Second Model.

Front sight Late First Model Safety on a Late First Model
Right: Late style half moon front sight
Left: Late style safety without the safe position dimple
A Late First Model A Late First Model
Side views of a typical Late First Model
The last Late First Model
Serial № 209610. The last First Model
Note the milling at the back of the frame, characteristic of the First Model. This is the highest serial number observed on a First Model. Pistols 2000 serials later have the Second Model frame milling.

The 'A' Series

To confuse the issue, there are a group of pistols with all the characteristics of the late first model but with the safety indicator dimple. The serial numbers on these guns all start with the letter ‘A’. They seem to have their own serial number series and do not seem to be accounted for in the standard serial numbers. It is unknown if these were a special contract or ???. One of these pistols is factory nickel plated. From the observed serial numbers there appear to have been over 50,000 of these pistols made.

A Late First Model A Late First Model
Side views of an A Series First Model Serial № A11761
The Early First Model safety indicator dimple and the half moon front sight can be seen.
A Late First Model
Serial № A11761 stripped to components

The Second Model

In about 1930 and serial № 210,000 the frame of the gun was redesigned to accommodate the new Tokarev style grip plate attachment method. This uses an internal pivoting arm to retain the grip plates to the frame. Grip plates using this attachment method were made of plastic or hard rubber. To allow the use of the new system the milling of the grip area of the frame had to be changed. The new grip attachment mechanism does not work on the first model pistols. Guns after serial № 210,000 for a short period still had the threaded holes for the wooden grip plates but the internal milling of the grip area of the frame was changed. At around serial № 230000 (?) plastic Tokarev type grip plates came into general use. (Note that earlier pistols may have had plastic replacement grips retained by screws – Serial № 185208 illustrated in Zhuk).

An early Second Model An early Second Model
Serial № 211986 The earliest observed Second model.
This pistol still has the threaded holes for wooden grip plates.
An early Second Model An early Second Model An early Second Model
Serial № 209610 –First Model, Serial № 211986- Second Model with grip screw hole, Serial № 325010 – Second Model without grip screw hole.
Note the difference in the milling at the rear of the frame in the grip area. Serial № 211986 still has threaded hole for wooden grip plates, Serial № 325010 does not..
Early Second Model w/plastic grips
Serial № 229961 The earliest observed Second Model with plastic grip plates. Note that it still has the grip screw hole.

There are at least two versions of the plastic grips. One variety has TOZ on both sides for Tula Weapons Factory in Russian. The second being the replacement grips for early pistols as shown in the section on First Models.

To remove the Tokarev style grip plates, the magazine was removed from the grip and the front projection at the base of the magazine could be used to move the lever on the left side grip plate rearward until the locking arm cleared the cutout in the frame. The left grip plate could then be removed. With the left plate removed, the locking arm on the right grip plate could be rotated to allow removal of the right plate. With this system no extra tools were required.

A note: The plastic grip plates on the Korovin seem to have been fragile and are commonly encountered broken or chipped.

Back side of plastic grip plates Front side of plastic grip plates
Tokarev Style grip plates inside and outside details. The retainer springs are shown with the locking arms in open position. The metal piece seen in the center of the plates in the outside view is the head of a rivet which allows rotation of the retainer springs.
Note the characters “ТОЗ” on the grip plate which gave the Korovin pistol the name “TOZ” in the western world.

The highest number observed with the grip screw hole has been № 253250, which has wooden replacement (?) grip plates with vertical grooves like a WWII Tokarev TT33 (There are more of these around according to a Russian source). This pistol can be dated to the 1932-36 period by the rarely seen Acceptance Commission mark on the right side of the frame. The circled ‘Зр’ mark was introduced on the Nagant revolver in 1932 and used until 1936.

The threaded hole for the wooden style grip plates seems to have been eliminated at about serial 255000. A pistol in the 259000 range has the plastic grips and no threaded hole.

Korovin with vertically grooved grips Korovin with vertically grooved grips
Serial № 253250 with its vertically grooved wooden grips
Marks on the right side of Serial № 253250
The 1932-36 circled ‘Зр’ Acceptance Commission mark seen on Serial № 253250. This is the only example the author has seen with an AC mark.

A witness mark on the rear sight was introduced at around serial № 270000. Serial № 259842 does not have the witness mark and serial № 274118 does. The Second Model Korovins have the same rear sight and slide design as the First Model.

2nd Model sight w/o witness mark 2nd Model sight with witness mark
Left: Early 2nd Model without witness mark on rear sight. Right: Late 2nd Model has the witness mark.
Typical 2nd Model Korovin Nickeled Second Model
Left: A typical Second Model Korovin with plastic grips. Right: Nickel guns have been observed as well as the standard blued guns.

The Second Model Korovins seem to cover the serial number range from 210000 up to at least the high 380000 range.

The Third Model

The final model of the TK Korovin seems to have been introduced at around serial № 400000. 3rd model guns are scarce and there have been very few examples observed. The earliest serial observed is 403650 and the highest 514339.

Russian sources indicate that the 3rd Model was “beefed up” from the 2nd Model to try to control the more powerful 6.35x16 Tula cartridge with its 20% “improved” power. The slide is heavier and the relief cutouts at the front area of the bolt are gone. The rear sight has been changed and the gripping grooves at the rear of the slide angled.

Early 3rd Model
Serial № 403650 Earliest observed 3rd Model (Photo courtesy 7.62x54r)
3rd Model Korovin 3rd Model Korovin
Serial № 510696 A typical 3rd Model in rough condition. This pistol has an aluminum magazine!
3rd Model Korovin 3rd Model Korovin
Serial № 513489 Another typical 3rd Model

The slide changes

The relief milling on the slide has been removed. The gripping grooves on the rear of the slide are now slanted as opposed to the vertical grooves of the earlier models. Both models usually have 14 grooves. The rear sight base has been made narrower and the sight blade more robust

SLide comparison
Difference in milling of slide of 2nd Model (top) vs. a 3rd Model (bottom)
Detail of new slide milling
Side detail of the slide milling changes. The 3rd Model slide (top) has slanted grooves, a narrowed sight base and no relief cuts.
Vertical Slide Comparison
Vertical view of the rear sight and milling of a 2nd Model (top) and a 3rd Model (bottom).
Detail of the rear sights
Detail comparison of the rear sights of the 2nd (left) and 3rd Models The 2nd Model (left) has the wider sight base but the actual sight itself is much thicker on the 3rd Model.

General Specifications

Spec page from manual
Here is the specification page from an early 1930s Korovin manual. The manual shows Early First Model guns in its diagrams. The specification for ammunition is for the 6.35 mm Browning cartridge. It would seem that that is the ammunition originall intended for this gun.
General Specifications of the pistol “TK”
Caliber 6.35mm
1. Pistol 9 shot (8 cartridges in the magazine and 1 in the chamber
2. Caliber 6.35 mm
3. Cartridge (pistol Browning) 6.35 mm
4. Length of Pistol 127 mm
5. Length of the barrel 6.75 mm
6. Length of the rifled part of the barrel 52 mm
7. Number of lands and grooves 6
8. Height of the pistol 98 mm
9. Width of the pistol 24 mm
10. Weight of the pistol w/magazine empty 400-410 grams
11. Weight of pistol w/magazine loaded 480-490 grams
12. Weight of magazine w/o cartridges 33 grams
13. Muzzle velocity 228 meter/sec
14. Weight of a cartridge 5.3 grams
15. Length of a cartridge 23 mm
16. Weight of powder charge 0.08 gram
17. Weight of a bullet 3.2 grams
Note: Barrel length is really 6.75 cm

What happened to them? There appear to have been over one half million pistols manufactured, but there are almost never seen in the west. Information from Russia indicates that many failed with the higher power ammunition. Another source indicated that they were gathered up after the GPW and were crushed and melted down for scrap.


The holsters for the TK look like a miniature TT33 holster, sometimes with and sometimes without cleaning rod loops. However, I have never even seen a picture of a TK holster with loops for a cleaning rod. The early 1930s TK manual does not show a holster, but does show a cleaning rod in a disassembly picture. This is the only picture of a TK cleaning rod that I have seen. I would assume that it is a brass or steel rod with a loop like a miniature 1930s Nagant rod.

The TK pistol is odd in that it is slightly larger than a Browning 1906 and most other pocket 6.35mm guns but smaller than most 7.65 mm guns so its size is unusual.

The earliest holster I have looks to have been made from some other kind of holster. It has no clip pouch and a double belt loop;

Korovin Holster 1 Korovin Holster 1 back
This holster has no clip pouch
TK Holster
The next picture is of a holster probably from the 1930s. It is made of very heavy leather. It has a clip pouch, but no cleaning rod loops.
The next pictures are of a pair of WWII period holsters. One is clearly dated 1941.
Wartime TK holster Wartime TK holster
The first WWII Vintage TK holster. Both of these have a double belt loop and clip pouch.
1941 date on TK holster
Date stamp on the leather
WWII TK Holster 2
The second GPW vintage TK holster
Post war TK Holster
A post war Soviet TK holster. The leather on this one is like the Tokarev and Makarov holsters of the 1960s and 70s.
East Germen TK Holster? East German TK holster?
The last holster is interesting as it looks to be East German. I originally purchased it as a PSM holster, but it is too small. It fits a TK perfectly?!?


Magazines and Ammunition

To be continued ...

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