The “wrong” in the photo is a double-ended 12,7-mm cartridge in a steel lacquered sleeve.
It is located on the right. In this version, this cartridge existed only in experimental versions and was not adopted as a result, as a result. Like any other 12,7-mm cartridge in a steel sleeve. Still used ONLY brass sleeve.
In violation of the Resolution of the Central Committee of the CPSU and the USSR Council of Ministers on 20 January 1976, “On the conversion of bimetallic and brass sleeves on steel lacquered sleeves in order to reduce the consumption of non-ferrous metals” and in spite of the active and lengthy work in the USSR in this direction. So what's the problem? Let's take a quick look.
History The creation and testing of 12,7-mm and 7,62-mm multi-cartridge rounds is both complex and interesting and instructive. It is detailed in the fourth book of the monograph. "Small arms ammunition" V.N. Dvoryaninova, on the materials of which, basically, this brief review is based.
So, formally, the history of multi-pool "aviation»Cartridges begins on February 13, 1975, when the Main Directorate of the Air Force of the Ministry of Defense sent to the Main Directorate of Experimental Works (GUOR) of the Ministry of Defense Industry and TsNIITOCHMASH, with copies to the Design Bureau of Mechanical Engineering, Tula (KBP), TsKIB SOO and KB named after Mil, letter: "In pursuance of the [military-industrial complex] decision of 04.12.1974/XNUMX/XNUMX, I am sending for TTT approval for the creation of a high-speed machine-gun complex for arming helicopters ..." (code "Theorist"). Attached to the letter were tactical and technical requirements (TTT) approved by the customer and agreed with TsKIB SOO and KBP. Judging by the dates of approval, the initiative to develop these TTTs came from TsKIB SOO.
According to the ROC "Theorist", with reservations mandatory in such cases, it was envisaged to create 12,7-mm five-point and 7,62-mm three-pole cartridges for new Tul 4-x barrel guns TKB-063 and TKB-621, later named YakB-12,7 (9-А-624) and GSHG-7,62 (9-А-622). Immediately OCD ... Tight deadlines ... At the same time, there were no preliminary studies of TsNIITOCHMASH in the form of research and there was no “reserve” on this subject. But the "theme" was issued, practically, forcibly! And as soon as TsNIITOCHMASH, appointed by the responsible executive, did not “put forward reasonable objections,” the work began.
An important question: where does this topic come from and why has it gained such importance and momentum?
The development of both machine guns in Tula was officially launched back in 1968 year. The study and study of options, of course, were carried out earlier, since information about work abroad was available. Time of the Vietnam War. In the US Army, the 1956-mm six-barreled Vulcan aircraft cannon (M20 Vulcan) comes into service in the 61, in the year 1960 the 7,62-mm six-barreled Minigun.
7,62-mm machine gun M134 Minigun 1960-s.
Both samples - with a very high rate of fire: up to 6 thousand shots per minute. Moreover, in the calculations of our "effective workers" of that time, they were adopted a rate of fire equal to 8 thousands, since it was believed that the design weapons allows you to achieve that pace. Purpose and main application - for armament of helicopters and attack aircraft, Vietnamese theater of military operations. Against the accumulation of infantry and poorly protected targets such as "car" and so on.
GAU-17 / A is one of the modern versions of the 7,62-mm Minigun. Photo 2006 of the year.
The theory of the "shower of fire" was very popular with the military at that time. And the need to create a combat helicopter complex on the principle of "flying infantry fighting vehicles", equipped with high-paced gun-and-cannon armament, was not in doubt. The backlog of Soviet developments in this direction was necessary not only urgently to eliminate, but also to make their system "better", of course. Such is the competition in the rate of fire, the density of "shower" of bullets, in relation to weapons ...
But the problem is that the scheme of our machine guns chosen by weights and other design considerations is four-barreled, without electric drive - as a result, it allowed to achieve the rate of fire “only” in 4 - 5 thousand rounds per minute (in normal conditions). What was clearly not enough to get ahead. That is why there was, first, a proposal, and then - the urgent requirement to create multi-ammunition and, thus, get a fantastic equivalent density of fire. Imagine: 5-bullet ammunition with 5 thousands of shots / min = 25 thousands !!! Even the three- and two-pool variants promised, according to calculations, a significant advantage and efficiency.
By the way, about the effectiveness of multipulse. Different sources give practically identical figures on the superiority in efficiency of hitting targets for double-bullet cartridges. Which are taken from the calculations of 1976, the department of efficiency TSNIITOCHMASH, performed in the framework of the ROC "Teoretik". Here are these figures, calculated for firing two-boom experienced cartridges from 4-x barrel guns GSHG and YakB installed in the helicopter's suspended gondola (such as Mi-24):
Indeed, the increase in efficiency should be 1,3 - 1,7 times. By the same calculations, it was determined that "according to the criterion of" cost-effectiveness ", the machine-gun complex with two-bullet cartridges exceeds the standard [cheaper] 1,2 - 1,5 times".
All just great! Only in the same report it was stated that these figures are correct for the calculations "without taking into account the influence of the opposition of the enemy." And further: “calculations specialists KB them. A mile when taking into account the fire resistance of the enemy showed that when firing at the Infantry Division goal, the advantage of two-round cartridges in relation to the standard cartridges is: 7,62 mm caliber - 13%, 12 mm caliber - 17%". That is, if the helicopter is forced to make anti-aircraft or other maneuvers when firing, “leaving” from enemy fire, then the efficiency sharply decreased. It is important to know to understand the further fate of the concept of the "shower of fire" and these types of weapons ...
So, in 1975, CNIITOCHMASH was issued by OCT “Theorist”. During the work, considerable time and effort had to be made to substantiate and prove the position of the patrons, that it was constructively impossible to create 3-x and 5-ty bullet cartridges in the given dimensions and requirements for bullet energy at a distance of 1000 meters. As a result, experimental versions of cartridges were developed: 12,7-mm two-stroke 1SL in a brass sleeve, which received the Air Force index "9-А-4012" and 7,62х54-mm two-cartridge cartridge that received the Air Force index "9-А-4011".
The history of the development of these cartridges is described in detail in the fourth book. "Modern domestic cartridges, chronicles of designers" monographs V.N. Noblemanova "Small arms ammunition"where a whole chapter is devoted to this topic, containing not only a summary of the history of their creation, but also a large number of drawings, diagrams, and test results.
In the period from 30.05 ... 31.08.1977 of the year to verify the compliance of TTT with experienced aviation systems (machine guns and ammunition), already at the technical design stage, in TsNIITOCHMASH experimental batches of two-bullet cartridges were manufactured and tested. Both batches of experimental cartridges during acceptance tests met the requirements of the drawing in terms of weight and geometry, ballistic characteristics and accuracy of shooting from a ballistic weapon. The test results of both batches of two-cartridge cartridges from TKB-621 and TKB-063 machine guns also turned out to be positive.
And 17.07.1978, the 12,7-mm 1CL cartridge drawings were approved by the PZ 493 (Customer Representation) with the addition: “For an experimental batch for state tests”.
But, around the same period, quite important events for our history took place: in 1977, both experienced 4's gun barrels were put into service. The Tula gunsmiths, the KBP and TsKIB SOO, presented developed weapons to the state tests. In the “kit” with regular 12,7x108-mm and 7,62x54-mm cartridges. Machine guns received indexes of air forces 9-А-624 and 9-А-622, respectively. The history of the development and "refinement" of weapons, in itself, is very interesting and complex. Designers had to consistently solve a large number of serious problems with reliability, survivability, adaptability, and so on.
Machine guns GSHG-7,62 and YakB-12,7 in a suspended helicopter gondola GUV-8700.
Machine gun YakB-12,7 in remote mobile installation USPU-24.
But how did the adoption of machine guns on the armament of cartridge manufacturers, who continued the development of two-round ammunition, influenced? Enough to mention this:
At first, now in all tests it was permissible to use only the weapon’s standard weapons and the design of the weapon no longer implied the possibility of revising the machine guns to “coordinate” the operation of the weapon-cartridge complex;
SecondlyThe design of the GSHG 7,62-mm machine gun has undergone such significant changes (in no way coordinated with TsNIITOCHMASH as the lead and responsible performer) in terms of the gas engine automation device that in 1978 the tests of the experienced cartridges on these machine guns were disrupted, since “the machine guns supplied by The new 9-А-622 index during the control check on OTT VVS-65 when firing at a temperature of minus 60 ° С did not ensure the possibility of firing experienced cartridges ... This circumstance with the 9-А-622 machine guns led to the possibility of conducting preliminary tests of experimental 7,62-mm two-cartridge ammunition and the manufacture of a land lot of ammunition for state tests ". Tritely there was not enough energy in the powder charge of the experienced cartridges for the promotion of the barrel unit with the “new and significantly simplified” gas-driven automatics of the modified GSHG machine gun;
ThirdlyThe trajectory of the bullets of the experienced two-bullet cartridges did not mate with the regular 12,7-mm cartridges due to different ballistics. And the aiming complex of the MI-24 helicopter (the onboard computer of the BWA-24) was “tuned” to the machine guns that had become overnight, under the standard cartridges and the corresponding ballistics.
According to the test results, the experienced two-stroke 12,7-mm cartridges satisfied the TTT in almost all requirements, including the reliability of the weapon. At the same time, a sufficient number of technical, technological and organizational issues remained. These are “protracted” shots, gunpowder, primers, and hermetic sealing and, in general, much more complicated air force requirements (OTT BBC-65 and FROM BBC-76), which are not familiar to cartridge plants, with their sophisticated technology. by "land" standards. After all, the 12,7-mm cartridge was, above all, a regular "land" cartridge!
The inability to show the customer the test results of 7,62-mm dual-cartridge cartridges created another serious problem - how to close the ROC “Theorist”? But an exit on the closure of the ROC "Theorist" was found. The 1SL cartridges with the 9-A-624 machine gun (YakB-12,7) were recommended for state tests, and the 7,62-mm double-cartridge cartridge with the 9-A-622 machine gun - for revision according to the new research project “Double”. Additionally, the research department "Dubl" included the requirement for testing the 12,7-mm 1SL cartridge with a steel lacquered sleeve, developed by KBAL and the Ulyanovsk Machine Building Plant since 1966. The resolution of the Central Committee of the CPSU and USSR Council on 20 January 1976 "On the transfer of bimetallic and brass sleeves on steel lacquered sleeves to reduce the consumption of non-ferrous metals" was already mentioned above, and this resolution had to be implemented - the new cartridge in the brass sleeve was adopted just not real ...
Without going into other details (which are in the 4 book of the monograph), we note only the following, the most interesting facts:
- two-bullet cartridge caliber 12,7 mm IN THE BRASS SLEEVE for the YakB-12,7 machine gun, developed by TsNIITOCHMASH by order of the USSR Defense Minister from 08.01.1982, No. 12 adopted by the Air Force with the following tactical and technical characteristics: cartridge length 147 mm, weight of the 145 cartridge g g 31 g bullets, the initial speed of the first 730 bullet m / s, the second bullet - 670 m / s, armor penetration at a distance of 1000 m - 5 mm;
- finally, all the “minor” problems for the 1CL cartridge were resolved only by 1986 year (we had to develop a new transport package, introduce a new type of sealant, finally work out the stability of the internal ballistics, ensure full compliance with the OTT Air Force requirements, invent a new method of fastening a shorter (relatively standard) ) the first bullet in a regular cartridge case and other stuff, etc.);
- The VSB-24 on-board computer, despite the lengthy correspondence and simplicity of its refinement, was not finalized. Xnumx plant them. Mile reported: “At the request of TsKIB SOO from 18.09.1984 and TsNIITOCHMASH from 15.06.1984, we inform you that the ballistics of the cartridge 08.08.1984СЛ has not been entered into the calculators of the sights of the Mi-1В, Mi-24Д and Mi-24П helicopters due to the lack of technical capabilities. The use of two-bullets in ammunition of these helicopters is possible. In this case, corrections for aiming are taken from the tables. However, the absence of tracers in two-bullet cartridges does not allow to correct the shooting, which significantly reduces the accuracy of shooting. " And such a cartridge was developed by order of the Air Force. By order of the Minister of Defense of 24, the 05.01.1989-mm two-bullet cartridge with the 12,7-SLT tracer bullet (1-A-9 air force index) was adopted for the Air Force;
“Finally, in 1981, the development of 7,62-mm dual-cartridge cartridges was discontinued. Since "The use of the two-cartridge cartridge for the GSHG-7,62 machine gun does not increase the combat effectiveness due to the inevitably low energy of each bullet compared to the conventional cartridge, which drastically reduces the damaging effect on targets." Which, by the way, the TSNIITOCHMASH cartridge producers tried to prove to no avail even in the 1975 year, when they were given the task of developing ... a three-core 7,62-mm cartridge;
- “Land” military closely followed the progress and results of the work on the creation of two-cartridge cartridges for the Air Force. Especially. that in due time, Grau initiated a similar research at TsNIITOMASH for 7,62х39-mm automaton (sample 1943) cartridges, which were discontinued at the R & D stage due to the obvious inefficiency of such cartridges. Miracles did not happen this time. Concerning the two-bullet 12,7-mm cartridges, the opinion of the GRAU was similar: in the 1979 year, the military unit 64176-E gave an expanded opinion after conducting the CNIITOCHMASH optional testing of the performance of the 12,7-mm machine guns arr. 1938 / 46 (DShKM) and NSV-12,7 (6P11): "12,7-mm two-cartridge cartridge 1СЛ when firing small arms of the Ground Forces can be of limited use due to reduced armor penetration, the need to rework sighting devices and less reliable operation of the machine gun." In the 1983 year, more definitely: “In the Ground Forces, large-caliber machine guns are primarily designed to destroy lightly armored vehicles and low-flying air targets. The use of dual-bullet cartridges to combat the above targets, the accuracy of which is worse in 2,5 and the energy characteristics of bullets at a distance of 1000 m in 3 - 4 are lower than that of a regular cartridge, according to GRAU, will reduce the effectiveness of the weapon. In addition, the external ballistic characteristics of standard and double-bullet bullets differ, making it impossible to conduct aimed fire from machine guns without reworking their aiming devices. Based on the aforesaid, GRAU MO considers it inappropriate to use two-shot cartridges for firing from 12,7-mm machine guns DShKM and NSV-12,7 ".
It remains to be explained - why the steel varnished sleeve never became standard for 12,7-mm cartridges.
In principle, its development was conducted by KBAL (Klimovsk) and the Ulyanovsk Machine Building Plant. When a new phase began in 1981, within the framework of the OCD “Double”, TsNIITOCHMASH planned to use in its development a two-cartridge cartridge (called the 1SJ) an almost ready, so to speak, full-time metal sleeve. The first batch of experienced steel liners were tested by shooting for durability and reliability of the operation of an infantry machine gun arr. 1938 / 46 (DShKM) and from the aviation machine gun A-12,7A. When conducting control tests in TsNIITOCHMASH in the IV quarter. 1969, when shooting with a machine gun DShKM was received an increased number of delays due to the departure of ammunition from the link tape. For durability and all other characteristics, 12,7-mm cartridges with a steel sleeve satisfy the TTT. Therefore, in a joint conclusion of the CNIITOCHMASH and PZ 2321, according to the test results, the cartridges with a steel sleeve were recommended for serial production, subject to the use and approval of the tape used for the DShKM machine gun used in the NSV-12,7 experimental infantry machine gun, instead of the standard tape.
At the beginning of the 1970's NSVT-12,7 and NSVT machine guns were adopted by the Army. In 1977, the test for shooting 12,7-mm cartridges was introduced with the shooting of a NSVT machine gun (tank version of the NSV-12,7 machine gun). The version with a steel sleeve fully complied with the requirements and the decision of the GRAU from 27.11.1978, the design documentation for the 12,7-mm cartridge with a steel lacquered sleeve was approved.
No one foresaw the insoluble difficulties from the side of the liner.
However, during the tests of the experienced 1SJ cartridges in the third quarter of 1981, a big trouble happened - “at the holding temperature of a machine gun with ammunition at minus 60 ° C, a high percentage of cartridges with longitudinal cracks along the slot and, in part, along the slope - 60,9%, on brass sleeves is obtained 1SL cartridges no cracks. " Under normal conditions, an unacceptably high percentage of liners with cracks along the ramp and Dultz was also recorded. Began to understand. It revealed:
«Comparison of the drawing geometric dimensions of the chamber chambers of the DShKM, NSV-12,7 and 9-A-624 machine guns shows that the chamber of the NSV-12,7 and 9-A-624 machine guns, developed by TsKIB SOO, have different sizes in the area of the part of the skate and the XA and 9, which have different sizes in the area of the part of the skate and the XA and 624. The presence on the 12,7-A-XNUMX machine gun of large relative radial clearances between the cartridge case and the chamber and the sharp difference in diameters of the cartridge chamber at the location of the sleeve case results in significant irregular radial deformations and re-clamping of the case sleeve during firing. The plastic properties of the metal of the brass sleeve of regular XNUMX-mm cartridges provide this degree of deformation and the sleeve does not collapse. A steel sleeve, especially at negative temperatures, does not withstand such radial deformations, as a result of which longitudinal cracks are formed in this zone.
Thus, the cause of the longitudinal cracks on the steel barrel of the varnished 12,7-mm sleeve of the two-cartridge cartridge 1СЖ is the large radial clearances provided by the drawing of the chamber of the 9-A-62 serial machine gun».
The difference in size really turned out to be significant: the diameter of the chamber in this place at the AESC is, mm: 14,08, in NSV-12,7 - 14,28, in YakB-12,7 - 14,78. In addition, the size of the mirror clearances (between the bottom of the liner and the mirror of the bolt) for all machine guns is also different. In DShKM - from minus 0,02 mm. to plus 0,008 mm .; YakB-12,7 - up to 0,5 mm. This is a very significant difference. Accordingly, the conditions of operation of the sleeve in each of the machine guns are different.
Gunsmiths, of course, refused to make changes to their drawings. Since these amazing sizes appeared for a reason and not as a result of an error or oversight. Yes, and the weapon was taken into service, did not withdraw the same machine guns?
Here's how today (in 2015) explains the causes of problems with transverse cliffs of sleeves, the author of the monograph "Small arms ammunition" V.N. Noblemen, in those years, the head of department №23, who was the head and responsible executor for ROC "Double":
«Theoretically, at the beginning of the shot, the liner under the action of the pressure of powder gases on its bottom is thrown back, choosing a mirror gap. More precisely - after the bullet has moved, the pressure of gases on the bottom of the liner is much higher than the pressure on the walls of the liner in the direction of the barrel. As a result, the sleeve should begin to shift towards the bottom, choosing a mirror gap. It should, but, as they say, is not obliged. This process takes place in a short period of time after overcoming the bullet-removing effort (the expansion pressure).
While the pressure inside the sleeve rises to the level of the force removing the bullet, the sleeve remains stationary in the longitudinal direction and, under the action of the pressure of the gases, swells in the radial direction and begins to press against the walls of the chamber. Moreover, this process begins with the barrel and upper part of the liner body, where the wall thickness is minimal. By the time the bullet starts to exit the barrel, the pressing force of the sleeve to the walls of the chamber may be so great that the force of holding the sleeve by friction forces in the longitudinal direction exceeds the force from the gas pressure to the bottom of the sleeve and does not throw the sleeve back. It as it were pinched in the upper part. And the sleeve begins to stretch in the longitudinal direction, choosing not only the mirror gap, but also the elastic deformation of the locking assembly in the axial direction.
The maximum maximum spreading pressure in 12,7-mm cartridges could reach 452 kg / cm2. This is quite enough for a soft and thin-walled brass sleeve to be pressed against the walls of the chamber at a great length by the time of unzipping and could not be thrown back by gases. And in combination with the mirror clearance increased on aircraft machine guns, this most likely led to separate cases of transverse shell breaks during firing, which is completely unacceptable in multi-barrel systems. So the designers decided to solve the problem in the simplest way - by reducing the length of the sleeve contact with the chamber in the initial period of its deformation by boring the chamber in the “problem” place - in the Dultz area and the beginning of the slope».
That is, gunsmiths to ensure the reliability of the weapon, the more so complex and capricious as multi-barrel high-temperature systems, on the one hand laid an increased mirror gap, on the other hand - they used the well-known method of boring the chamber. Looking at the dimensions of the chamber houses, it can be seen how for A-12,7 and NSV-12,7 “enough” two-tenths of the bore. And for YakB-12,7 - they allowed themselves to add another five tenths. Total difference is ten-tenths. From the possible longitudinal cliffs and tight extraction of the brass sleeve got rid of. At that time no one would have guessed that a steel sheath would appear and would not survive such “improvements” ...
In order to exclude such cases in the future, 03.05.1983 of 5 and 4 GU MOP approved the instruction developed by TsNIITOCHMASH “On the procedure for developing, coordinating and making changes to the drawings of the chamber and the barrel of a ballistic, combat and rifled sporting and hunting weapon” agreed with KBP, TsKIB Soo and kbal.
The patrons, of course, made every possible effort to solve the problem. But the difference in size was so great for a steel sleeve that nothing helped. Solving the problem due to the design and dimensions of the liner - for one system, the desired result was obtained, but for others - tight extraction or other unacceptable results in terms of reliability.
In addition, the fourth Main Directorate of the Ministry of Defense Industry in May 1982 ordered to conduct tests of regular 12,7-mm cartridges, including from the YakB-12,7 machine gun, since the Air Force used these cartridges. And it finally buried attempts to introduce a steel lacquered sleeve for 12,7-mm cartridges in general, since "it did not work."
The story with the steel lacquered sleeve for regular 12,7-mm one- and two-bullet cartridges is over. The sleeve for them is still brass.
As for the fate of the two-12,7-mm 1SL and 1SLT cartridges, as well as the small arms and guns of our helicopters, then, briefly, their fate was as follows.
Initially, one YakB-12,7 and two GSHG-7,62 were installed in a single gondola. But GSHG quickly disappeared from this composition and YKB "remained in splendid isolation." The machine gun itself was refined in the direction of reliability, rate of fire and increase in the life of the barrel survivability, getting the name Yakbyu-12,7.
Interestingly, the Air Force favored regular single-cartridge 12,7-mm cartridges. Most likely, because it is easy to shoot two-bullet “ballistic tables”, or it is easy to adjust the fire on the tracers only in theory and at the test site. And many of our combat helicopters have never encountered dual-cartridge ammunition in practice.
In addition to all this, in the 1982 for the Air Force, the Azimut-2 research and development work on justifying the armament of prospective helicopters was completed, and the irrationality of the armament of these aircraft 12,7-mm machine guns was established by research. In the MI-24 helicopters in the part of the standard stelkovo-gun armament began to install aircraft double-barreled guns GSH-23, GSH-30-2. The tempting and beautiful concept of the “shower of fire” also did not fully justify itself ... In 2010, the 12,7-mm cartridges of the 1CL and 1-SLT were withdrawn from production and from the weapons of the Russian Army.
The most important thing in this whole story is the obviousness of the fact that there is no “senior” or “junior” weapon in any military complex. Only a good understanding of all the nuances of the design and operation of both the elements of the weapon and the cartridge can bring overall success and a positive result. And each “trifle”, insignificant at first glance, threatens with its own surprises.
© November 2015
© November 2015
In preparing this article the following materials were used:
- V.N. Noblemen. Book-4 "Modern domestic cartridges, chronicles of designers" (ISBN 978-5-9906267-3-7) монографии "Small arms ammunition", ISBN 978-5-9906267-0-6. D'Solo Publishing House, Klimovsk, 2015.
- Own photographs and drawings of the authors;
- Materials free encyclopedia "Wikipedia";
- N.G. Menshikov. Album designs of small-bore and large-caliber automatic weapons. Publisher Artillery Academy. F.E. Dzerzhinsky, M., 1946.