Military Review

Experimental machine Shiryaeva AO-27

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In the late fifties and early sixties in the USSR, designers Dvoryaninov and Shiryayev carried out work on subcaliber swept ammunition. In 1961, Shiryayev created an experimental machine gun AO-27 for these munitions.


Tests showed a very good flatness of low-sized feathered bullets, but accuracy, somewhat inferior to conventional ammunition.



The automatic machine AO-27 designed by DI Shiryaev is an integral part of the experimental complex "weapon - cartridge with arrow-shaped bullet ", developed at SRI-61 (later - TsNIITochMash) since 1960. By that time, a number of studies aimed at improving the effectiveness of the AK-47 when firing from unstable positions (standing and from the knee) were completed. As a result, it was found that the most acceptable way to solve this problem is to reduce the recoil momentum, in order to maintain and even increase the range of a direct shot, it was necessary to reduce the caliber.

To a similar conclusion previously came to the United States, where the cartridge and automatic caliber 5,56 mm were developed. The creation of a domestic analogue of such a cartridge was initiated by the head of the cartridge direction of the SRI-61, V.M. Sabelnikov. As an alternative to the aviation armaments department of the scientific research institute-61, it was proposed to simultaneously check the possibility of using for the same purpose a cartridge with a sabotite arrow-shaped bullet. The hope for success was given by the fact that at that time domestic arrow-shaped armor-piercing sub-caliber shells with separating pallets to the 100-mm anti-tank gun T-12 "Rapier" had already been developed. The design of such ammunition, i.e. a cartridge with a feathered subcaliber arrow-shaped bullet and a detachable leading two-sector tray for automatic weapons, was developed in 1960 and protected by copyright certificate N 22527 with priority from 1 June 1960.

The authors of this invention are V.P. Gryazev, P.A. Fadeev, A.G. Shipunov and D.I. Shiryaev. The patron was assigned an index of OPS (feathered sub-caliber rifle). The AO-27 machine gun for these ammunition was developed at the start of the 1961 of the year. The ammunition OPS and automatic machine AO-27 for him represent the world's first rifle complex of this kind. Later, the Americans tried to realize this idea, but their long-term efforts in this direction were not crowned with success. Automatic equipment AO-27 of vapor type with removal of powder gases through a side opening in the wall of the barrel. As a barrel, regular blanks of 7,62 mm caliber were used, in which regular sections were cut, but more gentle. The rotation of the bullet contributed to a clear separation of the sectors of the pallets leading the bullet along the barrel. In addition, during the rotation of an aerodynamically stabilized bullet, the eccentricity of the forces acting on it averaged and, consequently, the scatter of hits decreased. The bolt is rotary, with two locking projections.

The stem of the bolt is structurally made together with the rod, ending with a gas piston. In the hollow piston rod of the gas piston is placed a return spring. The impact mechanism of a striker type with a long stroke (almost equal to the stroke of the shutter) of the striker. This was done in order to increase the time cycle of the automation to reduce the rate of fire. The trigger mechanism of the simplest type, consisting of a trigger, rotary sear, self-timer and uncoupler. The flag-type fuse-translator is located on the trigger guard behind the trigger + com, by analogy with self-loading rifles SVT. Aim devices consist of a pillar and front sight.

In the first version of the machine, the pillar was diopter and the front sight was located on the gas chamber. When developing the complex on the recommendation of the military, the sight was replaced with a conventional adjustable sector, and the adjustable front sight was transferred to the muzzle of the barrel. Shooting is performed from the so-called front sear, i.e. with movable parts in the front position. According to the testing reports of the complex at the stage of the main designer, its advantage over the AK-47 was overwhelming. In particular, the range of the direct shot of the machine was 530 meters against the 356 AK-47 and 437 rifle rifles.

In this case, the recoil pulses were 0,5 for AO-27, 0,78 for AK-47 and 1,24 kgf for a rifle. When shooting at a distance of 1000 m, the trajectory heights were respectively 3, 10.5 and 6 meters. Large initial bullet speed OPS cartridge (1060 m / s) and lateral load gave the machine AO-27 a significant advantage in the penetration of such obstacles as trench ripples. Significantly less was the dispersion of the bullets of the AO-27 machine compared to the AK-47 when firing in short bursts from a standing position. But due to the weak stopping power and the high cost of the cartridge, the topic was left in the category of R & D.



Characteristics of the machine AO-27 and cartridge OPS:
Automatic
Weight of the machine with a magazine without cartridges, kg 3,2
The length of the machine, mm 893
Barrel length, mm 415
Number of magazine cartridges, pcs 30
Rate of fire, rds / min 700



Cartridge
Caliber barrel / bullet mm 7,62 / 3
Cartridge weight, g 10,5
Bullet weight, g 2,4
Cartridge length, mm 63
Bullet length mm 55
Maximum pressure of powder gases, kg / mm 2700
Initial bullet speed, m / s 1060
20 comments
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  1. Airman
    Airman 6 September 2013 09: 38 New
    +3
    The idea is very interesting, but the cost of the cartridges decided everything. But why not try this principle on sniper weapons?
    1. bunta
      bunta 6 September 2013 10: 51 New
      0
      Quote: Povshnik
      not try on sniper weapons?

      arrows will blow off the wind.
      1. bazilio
        bazilio 6 September 2013 13: 23 New
        +3
        Quote: bunta
        But why not try this principle on sniper weapons?

        low OPD due to small caliber. But such armor penetration is higher.

        In Austria, they created an AMR / IWS 2000 caliber of 15.2 mm, but this rifle is more likely not sniper but anti-material. In the series did not go. They (Steyr) created an ACR submachine gun under a cartridge with a sub-caliber arrow-shaped bullet. The machine did not go into the series.
        1. Kir
          Kir 6 September 2013 17: 13 New
          +2
          And the question is, what kind of special weapon is serial? This is the first and the other if they would continue to experiment, maybe both price and technological effectiveness led to mass entry into the troops, and it remains only to vaguely hope that the continuation will take place, but we still do not know this.
          1. bazilio
            bazilio 7 September 2013 11: 55 New
            0
            Quote: Kir
            And the question is, what kind of special weapon is serial? This is the first and the other if they would continue to experiment, maybe both price and manufacturability led to mass entry into the troops

            Mass weapons are not needed for special weapons, I agree. But what are the benefits of AO-27. Greater accuracy and range of a direct shot + armor penetration. On the other hand, low RPD of 3 mm bullet-arrows. Even if we discard the financial aspect, it is not clear what is preferable - more heap, long-range and armor-piercing ammunition with lesser operational efficiency or less long-range, armor-piercing but with higher operational efficiency. But regarding the comparison of SPD, it is definitely difficult to say something until there are empirically substantiated results on the SPD of ammunition for AO-27.
  2. gych
    gych 6 September 2013 10: 50 New
    0
    Ukrainian sniper rifle "Askoria" Tactical and technical
    characteristics :
    Total length (mm) 1165
    Total weight (kg) 7
    Ammunition Weight (g) 47
    Ammunition Length (mm) 124
    Caliber (mm) 13,2
    Bullet Weight (g) 17,5
    Initial bullet speed
    (m / s) 1500
    Maximum pressure (kg / cm2) 4500
    Store Capacity 5,7,9,11
    Armor piercing
    at a distance of 600m:
    steel sheet - 50mm
    bulletproof glass - 250mm. but as always we have either a short staircase or a paint delivery!
  3. bunta
    bunta 6 September 2013 10: 57 New
    +5
    Question to the author. Kgs is a kilogram-POWER, not an impulse. The momentum is measured in kilograms per meter per second.
  4. Yemelya
    Yemelya 6 September 2013 18: 42 New
    +2
    In connection with the progress in the creation of body armor, the idea can be embodied.
  5. Droid
    Droid 6 September 2013 19: 17 New
    +2
    Quote: bunta
    Kgs is a kilogram-POWER, not an impulse. The momentum is measured in kilograms per meter per second.

    There should be written kgf * s, which is quite an impulse. Why kgf * s is reduced to kgf is not clear.
    1. bunta
      bunta 7 September 2013 00: 23 New
      0
      Quote: Droid
      unclear.

      It is unclear what this is all about. A mechanical impulse is mass times velocity. For 7,62x54 this will be 0,0096kg * (800ms) = 7,68 kg * m / s. According to the law of conservation of momentum, a weapon will receive exactly the same impulse. Where is 1,24 from?
  6. Mr. Truth
    Mr. Truth 6 September 2013 20: 45 New
    0
    Sooner or later, everyone will come to SPEL in assault rifles.
  7. Cpa
    Cpa 7 September 2013 04: 08 New
    0
    I can imagine what a machine gun should be cleaned after firing with such cartridges. laughing
  8. Droid
    Droid 7 September 2013 08: 18 New
    +3
    Quote: bunta
    Quote: Droid
    unclear.

    It is unclear what this is all about. A mechanical impulse is mass times velocity. For 7,62x54 this will be 0,0096kg * (800ms) = 7,68 kg * m / s. According to the law of conservation of momentum, a weapon will receive exactly the same impulse. Where is 1,24 from?

    It’s completely clear. An impulse is not only m * v, but also F * t, and since in a technical system of units the force is measured in kgf, the impulse is in kgf * s.
    Your calculation shows the momentum of the bullet, not recoil. You forgot to consider the momentum of the powder gases. If we take them into account, the recoil momentum will be p = 9.6 * 0.835 + 1.275 * 3.27 = 12.19 N * s, which when converted to kgf * s will give p = 12.19 / g = 1,243 kgf * s
    1. bunta
      bunta 7 September 2013 09: 06 New
      0
      Thanks for the science, indeed the contribution of powder gases is solid. But it’s all the same about the characteristics of the cartridge. Not weapons. As the author writes. Returns are subjective :). It depends on the mass of the weapon, and on how the weapon is held in hands and on design features.
      1. tkhonov66
        tkhonov66 28 November 2014 14: 09 New
        0
        "...
        Returns are subjective.
        ... "
        .
        -?!
        - bestowal, dear, - it is quite-OBJECTIVE.
        All jet devices move quite objectively in space precisely because of the most objective action of the “recoil” that occurs when the fuel burned out in the engine expires ...
        8-)
        But with all of this from the OBJECTIVE return of small arms - the shooting subject experiences quite SUBJECTIVE FEELINGS.
        8-))
        .
        Learn the materiel more carefully, dear!
        8-)))
  9. old rats
    old rats 8 September 2013 06: 30 New
    0
    somehow watched a program about creating a new machine for two-medium shooting (count underwater). and the cartridges shown in the report are very similar to those in the article. probably remembered the development.
    1. bazilio
      bazilio 8 September 2013 14: 45 New
      0
      Quote: old rats
      somehow watched a program about creating a new machine for two-medium shooting (count underwater). and the cartridges shown in the report are very similar to those in the article. probably remembered the development.

      Not quite so - for a two-medium machine gun, namely underwater, elongated bullets are used. This is done to stabilize the bullet in the aquatic environment. For example, bullets with a 115 mm long bullet were made for the APS submarine. At the same time, the bullet nose was made flat to create a cavity, which stabilized the bullet while passing through the water. In a two-medium machine gun left a long bullet with a sight for underwater shooting.
      1. Mouse
        Mouse 14 September 2013 22: 01 New
        0
        Yeah, exactly.
  10. aleksandrs95
    aleksandrs95 11 September 2013 16: 04 New
    0
    For sniper weapons, the necessary development, it is necessary to try on a new material base, there is something here.
  11. Mouse
    Mouse 14 September 2013 23: 19 New
    0
    There was another development of an arrow-shaped bullet: for hunting smooth-bore weapons.
    It was called "Zenith", equipped in a regular folder sleeve. The range for an ordinary shotgun is amazing: up to 300 (!!!) meters. And these are not idle inventions, but the words of the designer D. Shiryaev himself.