Saturday 11 January 2020

Whisper Quiet

When firearms were invented, the loud noise produced by a gunshot was more of an advantage than a drawback, especially when it was used against "old school" armies. With time, the demoralizing effect of the sound and flame of a gunshot became effective only against savages, but became very troublesome for the weapon's operator. Introduction of various types of special forces made this issue a pressing one, and by the start of the 20th century inventors began to combat it.

The first gun suppressors appeared around the same time as car mufflers. Hiram Maxim Jr, the son of the famous machine gun's inventor, developed a device to suppress the sound of a gunshot in 1902. It is not known whether or not he had military applications in mind. The "M. Maxim suppressor" was advertised in sporting and hunting goods magazines. The device sold well, even Theodore Roosevelt, the president of the United States, had one.

Nagant revolver with a Bramit suppressor.

Maxim's ads claimed that his suppressors were used by the War Department and National Guard, but it's unlikely that this use was for combat. Most of Maxim's suppressors were designed for .22 or .32 caliber weapons. Some sources claim that General John Pershing made the first attempt to use them against Panco Villa's rebels.

However, the legendary rebel did not have a chance to face Springfields with suppressors, as well as other modern weapons, including reconnaissance aircraft. There is also information on rifles with suppressors being sent to Europe as a part of the American expeditionary force, but no data on their use in combat.

The USSR began working on suppressors in the early 1930s both within the Red Army Artillery Directorate and the OGPU. The army were most interested in suppressing the sound made by standard infantry equipment: submachine guns, rifles, machine guns. However, experiments performed at the Main Artillery Directorate proving grounds start in 1931 typically ended in failure. Various designs were proposed by various inventors, but they had the same decisive drawback. All of them were tested with ordinary ammunition that had supersonic muzzle velocity. Regardless of the design of the suppressor, a meaningful reduction in noise could not be achieved.

Classics from anti-Soviet brothers

The secret police had better success. The Special Department of the OGPU curated projects to design a suppressor for the Nagant revolver and other short-barrelled weapons. Development was done by an engineer from the People's Commissariat of Railways, Ivan Grigoryevich Mitin, who worked on suppressors since the 1920s, and his brother, Vasility Grigoryevich. In mid-1933 the Mitins were arrested by the Transport Department of the OGPU on the charge of creating an anti-Soviet organization.

A Degryaryev light machine gun with a Bramit suppressor.

Since the accusation was very serious, and even supported with evidence (the brothers did not take any effort to conceal their political views, and the elder brother even managed to write a poster calling to an uprising), the technical curators did not step in to protect the "terrorists". As a result, Ivan Mitin only returned to working on the Bramit (Brothers Mitin) suppressor in 1938 when he was moved from the Solovetskiy camp to the NKVD Special Technical Bureau. This time, the work was done for the military, who needed a suppressor for the 7.62 mm caliber rifle.

The first Bramit prototype was shown to Voroshilov, by then the People's Commissar of Defense, in late 1938. Kliment Yefremovich liked the suppressor, but he requested one change: replacing the threaded attachment with a bayonet-type one. This proposal was correct, as in combat conditions Red Army soldiers would have likely over-tightened the threads and stripped them, ruining the suppressor, or under-tightened them, and have it fly off during firing.

The improved Bramit was put through trials in 1940. In addition to the suppressor, the Special Technical Bureau developed a reduced muzzle velocity US round. A table for converting sight markings was etched on the suppressor itself, along with a warning that using regular ammunition with a heavy bullet was forbidden.

PPD with an integrated suppressor.

The Bramit consisted of a two chamber pipe. Each chamber ended with a rubber bushing. Initially, the bushings were supplied at a rate of one per 60 shots, but use in winter showed that the rubber acts significantly differently and wears out after 15-20 shots. Winter bushings had to be quickly developed from cold resistant rubber. The division between winter and summer types remained until 1943, when aircraft rubber received through Lend Lease was used for both.

In addition to the rifle, Mitin developed Bramit suppressors for the carbine and Nagant revolver.

Other Soviet designs

OKB-2 tried to develop its own Bramit-like suppressor for the DP light machine gun indexed SG-42 (special suppressor model 1942). The SG-42 showed a number of drawbacks during proving grounds trials, namely that the automatic mechanism didn't function when firing without bushings and with regular ammunition. The SG-42 started working normally after improvements were made. However, a variant of the Bramit was developed by then, which was accepted into service as the SG-DP (special suppressor for the DP).

Another attempt to break up Mitin's monopoly was a device developed at the GAU small arms proving ground in the first half of 1941. The device was a multi-chambered one: the inside had a steel spiral with an opening that the bullet would pass through, and the hull had 48 openings. Unlike the Bramit, the proving ground's device had no rubber bushings and was designed to use ordinary supersonic bullets. This likely proved fatal. The trials report stated the following:
"1. Usage characteristics:
  1. The suppressor needs a lot of time for installation and removal. 
  2. The suppressor heats up to much after 5 shots that it cannot be removed with a bare hand. 
  3. Aimed fire with the suppressor is worse than without the suppressor. For instance, when the breech opens the gases partially escape from the breech and hit the shooter in the face.  
  4. The suppressor has no effect on the amount of flame produced at dusk.  
 2. Ballistic characteristics:
  1. The suppressor has no effect on the muzzle velocity of a bullet. 
  2. The precision with the suppressor and without is practically identical 
  3. The grouping center with the suppressor moves 0.5 mils or 2 minutes down. The deviation is 3 minutes less with the suppressor attached: about 11 minutes without it and 8 minutes with. 
The suppressor has nearly no effect on the noise of firing a model 1940 self-loading rifle, and thus cannot be recommended for adoption by the Red Army or further improvement. 

Another direction of work was the attempt to create an SMG with an internal suppressor. This work was motivated by a captured EMP submachinegun, likely from a Brandenburg-800 saboteur group. An analogous weapon was submitted for trials a year later. Supporting documentation identified it as the 7.62 mm PPD-Bramit submachinegun, developed by the small arms group of the 4th NKVD Special Department. This time, the suppressor was not a removable component, but built into the SMG instead of the barrel shroud. Since the front was noticeably heavier, a foregrip was added. The disk magazine was also altered, as special ammunition was once again necessary. The normal TT pistol casing was combined with an L-type rifle bullet and reduced charge. If necessary, the gun could fire normal TT ammunition. In this case, a special insert had to be put into the magazine, as the stock round was shorter.

Gurevich silenced revolver.

Trials showed that the gun was not completely silent, but the reduction in noise was sufficient to make it difficult to identify the sound as a gunshot, and nearly any noise (wind, speech, the sound of driving) would muffle it. The lifespan of the rubber bushings was 70 rounds, or one magazine. The conclusion of the trials was that the item could be in demand by partisan units or other special forces. However, the GAU decided that a Bramit for the rifle and machine gun made the device for the submachine gun, which also required a difficult conversion, pointless.

Finally, Ye.S. Gurevich worked in another direction. If I.G. Mitin was the first to develop an ordinary suppressor in the USSR, then Gurevich implemented a solution with a gas cutoff, or as he put it "hydraulic transfer round". The first successful prototypes, two single-shot 5.6 and 6.5 mm pistols, were tested in late 1943. Trials showed that the concept was functional and technically achievable. Gurevich presented a battle-ready prototype, a 7.62 mm revolver, next year.

Principle of operation of Gurevich's silenced revolver: top - before firing, bottom - during firing. The bullet is propelled from the barrel by a jet of liquid.

Comparative trials of Gurevich's revolver and a Nagant with a Bramit suppressor showed that the new revolver was much quieter. In addition, the Nagant became louder as the rubber bushings wore out, the limit of which was 20 shots. In severe cold the rubber hardened and was knocked out with the first shot. Gurevich's special bullets remained functional up to a temperature of -75 degrees C thanks to a mixture of 60% ethanol and 40% glycerin.

In conclusion, modern suppressed weapons used by Russian spetsnaz, such as the AS "Val" assault rifle or PSS "Vul" pistol, trace their ancestry back to weapons designed during the Great Patriotic War. They were not as successful or popular as their descendants, but the foundation for future success was in place.

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