The Soviet Model PB Silenced Pistol
The handgun is an ideal candidate for suppression in instances where concealability of a quiet weapon with reasonable terminal ballistics is a goal. With some exceptions, these suppressed weapon systems consist of a conventional handgun with an extended, threaded barrel to which a suppressor is attached.
Integrally suppressed handguns are fairly common in .22 rimfire, especially in the United States. They are used for target practice, small game hunting, and occasionally for less honorable purposes. As the OSS High Standard HD Military, they saw some action in the clandestine services. They were also issued to pilots of the U2 spy plane used during the cold war. Military Armament Corporation manufactured a number of integrally suppressed Ruger MK-1 pistols as well as the Ruger 10/22 rifle for use behind the lines in Vietnam.
For centerfire handguns, numerous muzzle attaching sound suppressors are available, both currently and historically. While most attach by means of threads on an extended barrel, there have been a few effective quick-detach offerings. All suffer the requirement of ammunition selection. With the exception of the .45 ACP and the anemic .380 (9mm Kurtz), most ammunition is supersonic in a handgun to deliver maximum terminal effect. Supersonic bullets generate a significant supersonic signature. While this may not reveal the location of a shooter, it certainly alerts bystanders to the fact that a shot has been fired. Velocity control, without special ammunition, usually requires that propelling gases be vented from the barrel before the projectile has had a chance to exceed the speed of sound.
There have been a few (very few) handguns designed specifically to keep standard centerfire ammunition subsonic for suppressed use, and most were designed for covert, close range assassination weapons. One of the older designs dating back to World War II was the British Welrod (a single shot, magazine fed, .32 ACP handgun) and its cousin, the .32 Sleeve Pistol. The Soviets have designed several silenced handguns for similar purposes. Other than the captive piston weapons (such as the PSS), one of the more unique is the model PB, often misidentified as “P6.”
It is believed that the PB was designed and initially built at Tula Arsenal in the USSR during the Cold War period in the mid 1960s and is credited to designer A. A. Deryagin. Because of minor differences, it is thought that some were built by other factories, including in East Germany. Some of the earliest surfacing of this weapon was in Afghanistan after the Soviet armies abandoned their failed Afghan experiment in the mid 1980s. It appears that this weapon was issued to certain of the Spetnaz units.
The PB shares some cosmetics and functionality with the common issue Makarov PM pistol in caliber 9×18. As with the standard Makarov, it is a double action semiautomatic blowback utilizing the standard 8-round Makarov box magazine. The safety, like the PM safety, is located on the left side of the slide, and when engaged, drops the hammer on the locked firing pin. The magazine catch is in the heel of the butt, and the trigger permits both single and double action firing. This is where the similarities stop. Unlike the PM, the PB’s ported barrel reduces the velocity of the 9x18mm round to approximately 290 m/s (951 fps) instead of the 340 m/s (1,115 fps) of the standard pistol. While the overall appearance and operation is similar, it is a totally new pistol with the only interchangeable part being the magazine. Few of the PB pistols have been seen in the Western world, and most that have surfaced are in government collections. Little is known about this pistol and its exact origins. Published data is scarce and fragmentary.
The complete weapon has an overall length of approximately 310 mm (12.2 inches) and a height of 140 mm (5.51 inches). The weight of the complete unit is reported to be 970 grams (2.14 pounds). The suppressor consists of two parts: a primary suppression chamber built to surround the ported barrel and a separate, secondary muzzle suppressor. The suppressor tubes are 32 mm (1.26 inches) in diameter. While the suppressors themselves are not serialized, the host weapon frame carries the serial number in the normal Makarov location (left side, behind the grip). The slide is also serialized, but may or may not match the frame.
The primary suppressor is built surrounding the barrel, and incorporates alternating rows of 3 and 2 ports in the specimen we examined. There appeared to be no effort to align the ports with the rifling grooves, unlike many other Soviet suppressors using rifled barrels. Reports of some variants of the PB include four rows of five barrel ports spiraling with the rifling. The rearmost port is slightly over 40 mm (1.57 inches) from the bolt face and the last port is approximately 25 mm (0.98 inches) from the end of the barrel. There is a collar that slips to the rear of the barrel, forming the rear mount for the primary suppressor tube. The barrel does not protrude beyond the end of the front bushing, which contains interrupted female threads for attachment of the secondary removable suppressor. The outer tube is retained by an interrupted groove engaging the front of the frame after a quarter turn. The standard Makarov trigger guard disassembly post keeps the primary suppressor tube from rotating. There is a spring-loaded latch on the bottom front of the tube to lock the secondary suppressor in place and prevent unscrewing. The volume surrounding the barrel is filled with a roll of fine screen and a spring coil, the purpose of which is to absorb heat rapidly through its large surface area and to diffuse the gases escaping from the barrel ports. The front sight is mounted on the front of the primary suppressor tube, and the rear sights are slightly higher than normal to accommodate the higher front sight.
The slide on the PB has the appearance of being a standard PM Makarov slide that has had most parts forward of the bolt face and above the rails simply cut away. Appearances are somewhat deceptive. The weapon is a simple, unlocked breech blowback, and simply cutting away part of the slide would reduce slide mass and seriously increase rearward slide velocity. Mass was added to the slide by increasing the length and thickness of the slide rails, and there was some lengthening of the frame.
In the PM, the recoil spring surrounds the barrel, as in a number of small pistols, such as the Walther PPK series. This is obviously impossible with a suppressor completely surrounding the barrel. Instead, the recoil spring was relocated to sit vertically in the grip behind the magazine well, and the grip was thickened to accommodate the spring. The slide was coupled to the spring by a bell-crank on the right side of the magazine well. One arm of this piece engages a cutout in the bottom of the right rear of the slide, and the other arm has a roller that compresses the spring.
The secondary suppressor is a more conventional Soviet muzzle design and is easily disassembled for maintenance. The core of the suppressor consists of approximately five parts spot welded together: two sheet metal rails (top and bottom), the front cap, the rear mount, and the baffle stack. The baffle stack is fabricated from a piece of sheet steel that looks like slanted washers with tabs to be spot welded to the top and bottom rails. The flat baffles are set at approximately a 60 degree angle to the bore axis with the first and last baffles slanting the same direction and the middle one opposite. The rails are welded to the front end cap and the rear mount. Two small spring-loaded plungers in the front mount retain the suppressor tube on the baffle assembly. The rear mount slips over the end of the barrel, and the interrupted threads permit tightening the suppressor onto the PB with 1/4 turn. The plunger in the front mount of the primary suppressor keeps the secondary muzzle suppressor from unscrewing.
The PB was issued with a leather holster that stored the secondary suppressor separate from the weapon, which could be fired using only the primary suppressor.
Disassembly is fairly intuitive. To remove the secondary suppressor, the locking catch on the bottom of the primary suppressor is withdrawn rearward and the secondary suppressor twisted 90 degrees counterclockwise to remove it from the interrupted thread. As in field-stripping the standard PM Makarov, the trigger guard is depressed and the primary suppressor tube rotated 90 degrees counterclockwise. At this point, the primary suppressor can be pulled off the barrel revealing the screen packing. There is a button on the frame at the rear of the trigger guard (this is NOT a magazine release) that retains the one-piece grip. Pressing this allows the grip to be removed rearward, revealing the bell-crank actuator and recoil spring. Lifting out the actuator will allow the slide to be pulled to the rear and lifted off the frame. The secondary suppressor can be disassembled by pressing the small spring-loaded plunger locking the outer tube to the front end cap. The outer tube then removes to the rear.
Reassembly is pretty much the reverse of disassembly and is also fairly intuitive. However, there are a few points to remember. First, the trigger guard needs to be temporarily returned to lock the slide in position before replacing the bell-crank actuator. Second, when re-installing the grip, it needs to be slid forward with considerable force.
On two separate occasions, we had the opportunity to perform standard sound measurements on the same Makarov PB integrally suppressed pistol. Both were on the same weapon in the possession of a dealer in the United Kingdom. The first set of measurements were performed in mid 2001 and the second three years later in the fall of 2004. In both instances, measurements were performed at the reference location specified in Mil-Std-1474C (and D). These consisted of placing the microphone 1 meter (3.28 feet) to the left of the muzzle, 90 degrees to the bore axis, and 1.6 meters (5.25 feet) above grass. A-weighting was used. A string of seven measurements were obtained, first with a standard non-suppressed PM Makarov, and then with the PB integrally suppressed weapon. Ammunition was standard Soviet 9x18mm. On both occasions, the environmental conditions were comparable, and we observed only minimal (and insignificant) variations between the two measuring sessions.
One of the important calculations in evaluating a suppressed weapon is what is referred to as “first round pop.” This is simply how much louder the first round is compared to the average of remaining rounds, and it is generated by a secondary burning of partially burned powder particles detonating within the suppressor filled with air (oxygen). After the first round has been fired, there is no further oxygen left in the suppressor. In most designs, this can be significant (well over 6 dB), and as little as 3 dB is obvious to the casual observer. First round pop can be eliminated by a number of techniques, including purging the suppressor of oxygen prior to firing. The majority of suppressors have a significant first round pop. In covert use, the sound level of the first round is the only one that counts.
The non-suppressed average was 158.9 dB in 2001 and 158.2 dB in 2004. This difference is considered to be meaningless. The suppressed Makarov PB had an average sound pressure level of 127.5 dB for a net reduction of 31.4 dB. Although the absolute sound level is comparable to a suppressed Beretta M9 (9x19mm) with a current design thread mounting muzzle suppressor, the lower velocity projectile from the PB generated a lower tone which was less noticeable. We did not measure the sound level of the weapon with just the primary suppressor by itself. Further, in both measuring sessions, the first round was only 1.5 dB louder than subsequent rounds – an important consideration in a weapon designed for covert usage.
In summary, the Makarov PB integrally suppressed pistol is a highly effective covert weapon. It has a bulky appearance, but it is more compact than conventional pistols with a screw-on muzzle suppressor. It consists of a special-design 9x18mm pistol and utilizes two suppressors on the same weapon. The secondary muzzle suppressor is easily removed for concealability but can be re-attached quickly. Although it can be used without the secondary muzzle suppressor, maximum effect is obtained when the weapon is used as designed. It has the advantage of velocity control to keep standard issue ammunition subsonic. While the lower velocity does slightly reduce the kinetic energy of the projectile, the soft sound signature is ideal for its intended purpose: close range assassination.
The author is indebted to the staff and personnel of the Firearms Technology Center of the Royal Armouries (UK) and its predecessor (MOD Pattern Room) for the opportunity to examine, disassemble, and photograph this weapon.