How 3 round burst works?

Discussion in 'Land Forces' started by arnabmit, Mar 21, 2013.

  1. arnabmit

    arnabmit Homo Communis Indus Senior Member

    Joined:
    Dec 25, 2012
    Messages:
    5,894
    Likes Received:
    5,859
    Location:
    Kolkata
    I am very interested to know how the 3 round burst in ARs work?

    I came to know via Google that most ARs use a rachet mechanism to count out the 3 rounds before locking the hammer. However this means in burst mode if you quickly release the trigger, it will fire only 1-2 rounds. Pressing the trigger again fires out only the remaining bullet out of the group of 3.

    H&K came up with a mechanism which lets you fire a 3 round burst every time irrespective of how many rounds were fired in the previous burst.

    Maybe someone who works/worked in an armory can shed some light
     
  2.  
  3. arnabmit

    arnabmit Homo Communis Indus Senior Member

    Joined:
    Dec 25, 2012
    Messages:
    5,894
    Likes Received:
    5,859
    Location:
    Kolkata
  4. arnabmit

    arnabmit Homo Communis Indus Senior Member

    Joined:
    Dec 25, 2012
    Messages:
    5,894
    Likes Received:
    5,859
    Location:
    Kolkata
    [video=youtube_share;ArNzI4Tdcvw]http://youtu.be/ArNzI4Tdcvw[/video]
     
    W.G.Ewald likes this.
  5. arnabmit

    arnabmit Homo Communis Indus Senior Member

    Joined:
    Dec 25, 2012
    Messages:
    5,894
    Likes Received:
    5,859
    Location:
    Kolkata
    [video=youtube_share;KtLJmgcVazw]http://youtu.be/KtLJmgcVazw[/video]

    [video=youtube_share;0Ot_SoFqD7A]http://youtu.be/0Ot_SoFqD7A[/video]
     
    W.G.Ewald likes this.
  6. arnabmit

    arnabmit Homo Communis Indus Senior Member

    Joined:
    Dec 25, 2012
    Messages:
    5,894
    Likes Received:
    5,859
    Location:
    Kolkata
    All of the videos above shows only Semi & Auto modes... None has the burst mode! :sad::sad::sad:
     
  7. W.G.Ewald

    W.G.Ewald Defence Professionals/ DFI member of 2 Defence Professionals

    Joined:
    Sep 28, 2011
    Messages:
    14,140
    Likes Received:
    8,528
    Location:
    North Carolina, USA
    M16A2 has semi-automatic and burst mode only.
     
  8. W.G.Ewald

    W.G.Ewald Defence Professionals/ DFI member of 2 Defence Professionals

    Joined:
    Sep 28, 2011
    Messages:
    14,140
    Likes Received:
    8,528
    Location:
    North Carolina, USA
    Burst mode (weapon) - Wikipedia, the free encyclopedia

    The functional check of the three-round burst is as follows:

    :: Guides
     
    Kunal Biswas likes this.
  9. arnabmit

    arnabmit Homo Communis Indus Senior Member

    Joined:
    Dec 25, 2012
    Messages:
    5,894
    Likes Received:
    5,859
    Location:
    Kolkata
    I guess those are civilian versions which has only the Semi mode as did not see the rachet assembly :sad:

     
  10. arnabmit

    arnabmit Homo Communis Indus Senior Member

    Joined:
    Dec 25, 2012
    Messages:
    5,894
    Likes Received:
    5,859
    Location:
    Kolkata
    Thanks! But any idea how the rachet is reset after an incomplete burst?

     
  11. W.G.Ewald

    W.G.Ewald Defence Professionals/ DFI member of 2 Defence Professionals

    Joined:
    Sep 28, 2011
    Messages:
    14,140
    Likes Received:
    8,528
    Location:
    North Carolina, USA
    arnabmit likes this.
  12. arnabmit

    arnabmit Homo Communis Indus Senior Member

    Joined:
    Dec 25, 2012
    Messages:
    5,894
    Likes Received:
    5,859
    Location:
    Kolkata
    There seems to be 2 different trains of thought... Which one is better? 2 round burst or 3 round burst?

    ... in terms of ammo economy as well as accuracy & effectiveness.
     
  13. Kunal Biswas

    Kunal Biswas Member of the Year 2011 Moderator

    Joined:
    May 26, 2010
    Messages:
    27,599
    Likes Received:
    28,401
    Location:
    BHARAT, INDIA, HINDUSTHAN
    You can set the rate of fire by gas regulator, Afaik 3 rnd burst is ok so does 2, But i personally believe there should be 5 rnd burst at slower rate is good in suppressing enemy..
     
    arnabmit likes this.
  14. arnabmit

    arnabmit Homo Communis Indus Senior Member

    Joined:
    Dec 25, 2012
    Messages:
    5,894
    Likes Received:
    5,859
    Location:
    Kolkata
    But isn't suppression the job of the Squad Automatic Weapon?

     
  15. Kunal Biswas

    Kunal Biswas Member of the Year 2011 Moderator

    Joined:
    May 26, 2010
    Messages:
    27,599
    Likes Received:
    28,401
    Location:
    BHARAT, INDIA, HINDUSTHAN
    You dont have LMG always around you..

    Just a thought..

     
    arnabmit likes this.
  16. pmaitra

    pmaitra Moderator Moderator

    Joined:
    Mar 10, 2009
    Messages:
    31,650
    Likes Received:
    17,146
    Location:
    EST, USA
    Rule of 22

    I recall reading on one of the articles, or perhaps seeing in a documentary, where a Soviet veteran of the Afghan War was telling how they operated their 3 round bursts.

    Typically, they would keep all their weapons, in full auto mode. Their weapons were, of course, AK-74. Then, at combat time, all they had to do is, while firing, say "twenty-two;" i.e., pull the trigger when saying "twenty," and release it when saying "two." Now, I wonder whether they said it in Russian, or whether hey just said it in English. Whatever be the case, the effect was simple - a well practised soldier could effortlessly churn out volleys of 3 round bursts with the weapon in full auto mode. This also helped then to switch to full auto at will, without having to shift the mode lever.
     
    sayareakd, DivineHeretic and arnabmit like this.
  17. arnabmit

    arnabmit Homo Communis Indus Senior Member

    Joined:
    Dec 25, 2012
    Messages:
    5,894
    Likes Received:
    5,859
    Location:
    Kolkata
    As I mentioned in OP, most ARs use a ratchet mechanism to count out the 3 rounds before locking the hammer. However this means in burst mode if you quickly release the trigger, it will fire only 1-2 rounds. Pressing the trigger again fires out only the remaining bullet out of the group of 3.

    H&K came up with a mechanism which lets you fire a 3 round burst every time irrespective of how many rounds were fired in the previous burst.

    I found a few pics which shows the unique ratchet of H&K and it's trigger parts.

    [​IMG]

    [​IMG]

    [​IMG]

    I am really unable to understand the working mechanism...

    @W.G.Ewald @Kunal Biswas @sayareakd can you help?
     
    Last edited by a moderator: May 10, 2015
    sayareakd likes this.
  18. W.G.Ewald

    W.G.Ewald Defence Professionals/ DFI member of 2 Defence Professionals

    Joined:
    Sep 28, 2011
    Messages:
    14,140
    Likes Received:
    8,528
    Location:
    North Carolina, USA
    Not me. We were just starting to use breech loaders when I served :)

    Seriously, M16 was just replacing M14 when I qualified with the rifle. M14 was semi-auto; M16 was either semi- or full auto.

    The M16A2 had the 3-round burst capability but I never fired one.

    https://en.wikipedia.org/wiki/M16_rifle#M16A2
    https://en.wikipedia.org/wiki/Burst_mode_(weapon)

     
    Last edited: Jun 5, 2013
    arnabmit likes this.
  19. DivineHeretic

    DivineHeretic Senior Member Senior Member

    Joined:
    Jan 1, 2013
    Messages:
    1,050
    Likes Received:
    1,183
    Location:
    Assam
    Well, for medium range engagement (300+ metre ) the five round burst seems to be the norm even in LMG and HMG fire supression, especially in night firing.

    We saw this right from WW2 (WW1 had mostly water cooled jacket around the barrel which enabled longer continuous volleys) when both the American/British Browning MG teams would fire 5-7 round bursts for maximum effect at least ammunition expense, and especially to ensure the gun did not become too hot for operation. They traded high rate of fire for a longer period of sustained intermittent fire.

    Even now, the MGs (even the SAW) have tracers at 5 round seperation to enable the soldier to identify how accurate his shooting has been and take necesary correction. This is especialy done for night gunning. Thus a gunner will stop after the tracer round has been fired to check the accuracy of his shots.

    I'm not sure the IA uses tracers in their MGs, or even if such tracers are available to the IA.
     
    W.G.Ewald and Kunal Biswas like this.
  20. Ray

    Ray The Chairman Defence Professionals Moderator

    Joined:
    Apr 17, 2009
    Messages:
    43,118
    Likes Received:
    23,545
    Location:
    Somewhere
    Yes tracers are used in the IA.

    One after every four rounds.
     
  21. sayareakd

    sayareakd Moderator Moderator

    Joined:
    Feb 17, 2009
    Messages:
    15,624
    Likes Received:
    11,703
    The INSAS 1B1 has three modes- Safe, Semi and 3round Burst. The selector lever is identical in position to that of the FNC and is a well though out adaptation on an AKM type receiver. The design of the thumb piece is based more on the SLR design rather than that of the FNC. However, it is still not as ergonomic as planned and unless you have thumbs like E.T., you'll need relinquish your firm hold on the grip to actuate the selector. Very similar to the SLR, the safety position is top most, down about 70 degrees and you have semi, then to activate the tri-burst mechanism you'll need to rotate it almost 180 degrees. Take a look at the image below.

    [​IMG]

    The three round burst mechanism is a sheet metal encased module that sits on the left side of the trigger/sear shoulder. It works by way of a ratchet and pawl lock-work. It is a vitual clone of the FNC/CAL module and at least in theory, independent of the basic functioning of the trigger mechanism. i.e. in case it buggers up, semi will continue functioning. The red circle in the picture below shows the 3 round burst module.

    [​IMG]
     

Share This Page