Thanks to the Kalashnikov Gun Magazine, today we have a chance to take a look at one of the Soviet experimental sniper rifles/DMRs chambered in the 6x49mm caliber. The rifle is called TKB-0145S (ТКБ-0145С) and as one can expect from an experimental rifle, it has a lot of interesting and unusual design solutions.

The 6x49mm was a high-pressure cartridge launching 6mm projectiles at a high muzzle velocity of 1,150 m/s which is about 3,770 fps. It was supposed to replace the 7.62x54mmR cartridge in machine guns and sniper rifles. With such a high muzzle velocity, it was an extremely flat shooting cartridge. The bullet drop was minimal resulting in a long point blank range and the projectiles were also less affected by the wind. These characteristics of the cartridge would make it much easier to transition between the targets located at various distances and successfully hit them thus highly compensating the user error associated with distance and wind drift estimation. If you want to learn more about this cartridge, read Nathaniel F’s article.

Top to bottom: 5.45x39mm, 6x49mm, 7.62x54mmR. Image from www.modernfirearms.net

By the time this cartridge was developed, three Soviet design bureaus (TsKIB SOO, TsNII TochMash, and IzhMash) were tasked to develop machine guns and sniper rifles chambered in this caliber. The sniper rifle development project was called “Carabiner” (Карабинер).  In TsKIB SOO of Tula, the chief designer of the sniper rifle was Alexander Adov. He designed a number of different versions of the sniper rifle (TKB-0145, TKB-0145A, TKB-0145VA, TKB-0145M, TKB-0145K), however, the final version of Adov’s rifle was the TKB-0145S.

Alexander Adov

One of the key requirements of this project was to make the weapons compact to be able to issue them to armored vehicle troops and paratroopers, too. As you can see in the images, TKB-0145S is not only a bullpup rifle but also has a possibility to fold in half resulting in a folded length of 32.8″ (834mm) at a barrel length of 28.3″ (720mm). The hinge point of the rifle is located in front of the rear sight base. There is a spring-loaded latch on the barrel which catches the lug located on the rear on the receiver thus retaining the rifle on its folded position. Folding of the rifle does not require removal of the scope and the magazine. This feature decreases the time required to prepare the rifle for firing.

The TKB-0145S rifle is gas operated with a rather interesting gas system. There is no gas port drilled into the barrel. The gasses are vented into the system after they have left the muzzle. This is somewhat similar to the Bang system in terms of the general principle. This design solution was used to eliminate any possible effects of the gas system onto the bullet’s flight. Interestingly, the first portion of the gas system uses a stainless steel gas tube similar to that of AR-15. However, this is not a direct impingement system. The gas tube is only about 6-7″ long and it delivers the gasses from the muzzle chamber to a short stroke gas piston.

Another interesting design solution is the asymmetric shape of the bolt carrier with the recoil spring located on its right edge. Such bolt carrier results in a sloped shape of the top cover of the receiver converting it into a low profile cheek rest and eliminating the need of excessively elevated iron sights or scope.

On the left, you can see the rear view of the bolt carrier. Note the asymmetric recoil spring housing.

The charging handle of this rifle is extended way forward of the breech. Such layout makes it easier to reach the charging handle on the bullpup rifle and eliminates the need of having a charging handle slot in the top cover of the receiver. Some of the parts of the TKB-0145S rifle (bolt, bolt carrier, fire control group, magazine etc.) are based on the SVD rifle although they are not identical and are redesigned to fit the new cartridge and layout of the rifle. The safety selector lever (with safe and semi-auto positions) is located behind the magazine well. The link to the trigger is a pull type one which is supposed to provide a better and more consistent trigger pull than the push bar type linkage. The rifle is fed from ten round detachable box magazines which are similar to the SVD magazines. The magazine followers and the pistol grip are made of polymer. The handguard is made of wood.

The rear sight of the rifle is a folding aperture sight which is adjustable to up to 1,000 meters. The front sight is mounted on the gas block/flash hider combination device. Both iron sights are attached to the barrel which ensures their consistency and makes them independent from the folding mechanism. The rifle uses a side scope mounting rail and was supposed to use the PSO-1 scope borrowed from the SVD.

Although this rifle proved to be a promising design, it couldn’t make it to the field trials stage because at the beginning of the ’90s the project “Carabiner” was halted. There were only four TKB-0145S rifles ever produced. In the mid-’90s, Adov designed a civilian version of the rifle called OTs-41. The civilian rifle had a shorter barrel and was chambered in .308 Winchester. Other than the mentioned differences, the OTs-41 was pretty much identical to the TKB-0145S. For unknown reasons, the civilian version of the rifle was never produced either.

OTs-41, the civilian version of TKB-0145S rifle

There were three Russian patents awarded for this rifle design: #2046265, #2067741 and #2067739. Below you can find a couple of drawings from these patents.

Sources:

Chumak R. (2018, June 19). “Тульский «Карабинер». Винтовка ТКБ-0145С”. Kalashnikov Gun Magazine. Retrieved from: https://www.kalashnikov.ru/tulskij-karabiner/

Images from www.kalashnikov.ru, www.modernfirearms.net