Map predicted GPMG fire

Discussion in 'The Training Wing' started by gobbyidiot, Nov 9, 2008.

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  1. I was glancing through a book in WH Smith ("Sniper") and he was talking about using GPMG similar to the the way the Americans use .50 cal - high trajectory out to 3k. I remember reading the GPMG pamphlet - tracer burning out at 1,100, the beaten zone at 1800, an elliptical long lemon-shaped pattern, rounds will strike and skip...............but I didn't think it was possible to fire 7.62 out to 3k.

    How much oomph has it at that range - 100ft lbs and minor injury, or 300 and something serious?
     
  2. I thought it was 2k.
     
  3. So did I - 1800. But the bloke seemed to be talking about up in the air in a parabola.
     
  4. Can't remember exactly but map predicted GPMG SF fire is possible out to about 3km. A 7.62 round is still traveling pretty fast at 3km. Whether you hit anything, now that's a different question.
     
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  5. IIRC it's out to 2.8k with a pretty massive beaten zone.I actually had the fabloned cards with all the gen on them but those are long lost.

    And even at that range a 7.62mm is going to ruin your day if you are hit..

    Now lets talk about somthing altogether more manly......FPF!
     
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  6. There was talk in my day of getting an enhanced 7.62mm round for ranges over 3km. MPF was never intended to be for individual guns, only section upwards and for concentrated fire on area targets. The beaten zones are pretty horrendous at that range but if you get enough guns firing into the same area... Still, I remember thinking at the time that someone had just read a book on the Machine Gun Corps when they thought that one up.

    As a bit of trivia, that was why the drills were amended so that the single leg on the tripod was positioned to the front instead of the back - so that the gun could be elevated for high enough trajectories. Oh how we laughed to find that one out on Match 83.
     
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  7. And the old Vickers MMG was sighted to 3,000 yards
     
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  8. Can be done ,but,as someone who had recent op experince on here said unless you can get your enemy to hang around in a convient field not really going to get much use out of it in present operations.
     
  9. GPMG SF can be used as an 'indirect fire' weapon (eg at night) using procedures very similar to mortars. After all it comes with (or used to) a C2 sight unit and a dinky little aiming post.

    All that is needed is for a number of pre defined targets to be registered and corrections can be made from them.

    And if you have maybe four guns ripping out 20 round bursts the noise is something else!

    With respect to woody this ability was probably more use to the cold war warriors in a defence than it would be to current ops
     
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  10. Your getting c2 sight firing confused with map predicted firing .I think .
    both allow you to shot at thing you cant see .Never really been explained why I would know to shoot at things I cant see .Hopefully someone with a radio can see what needs shooting .
    Map predicted fire lets you do indirect fire out to 2.8km while c2 allows 1800m .Definatly more use in defence ,but could be of use in attack espically if your going to use a lot of smoke on a postion first .
     
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  11. OK... as you say with the C2 you can fire when the target is obscured but the sight unit does not restrict the range in any way - this depends on the gun and the ammo.

    Range tables do (or did) exist for 7.62 but I have never seen them.

    ps it used to be normal training for mortar officers to be able to incorporate GPMG SF into a mor fire plan

    So the answer to the original question is 'Yes'
     
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  12. Didn't do it on my course! I thought it was 2.5k for map predicted but then again I was the mortar officer!
     
  13. Hello gobbyidiot,

    I had the maximum ranges for various calibres listed somewhere,but can't find them at the moment.
    A little Googling suggests 3750m,about two and a quarter miles,for 7.62mm NATO.
    Bullets can go a lot farther than most people might imagine!

    A 146 grain 7.62mm bullet with a ballistic coefficient of 0.42 fired at 840 metres per second would have 3,350 Joules of energy at the muzzle.
    At 400 metres it has 1,562 Joules of energy,about the same as a 5.56mm round has at the muzzle.
    At 1,100 metres it is down to 430 Joules,about the same as the muzzle energy of a 9mm pistol round.
    By 3,000 metres the 7.62mm round has only 130 Joules of kinetic energy left but that is still as much as a .22LR rifle would have at the muzzle.

    With a 10 mph crosswind,windage at 3000 metres would be about 35 metres.
    At 900 metres range the bullet becomes subsonic,accuracy degrades as rounds pass through the sound barrier.

    Consequently the beaten zone would be so large,and target movement so great (the bullet would take over 11 seconds to reach 3,000 metres) that you would have to put down a lot of rounds through a lot of weapons to produce effective fire.
    One machine gun would still be useful for harrassing fire on known enemy positions though.

    The above is based on a standard ball round,as was said earlier there are special long range 7.62mm rounds which would go further and carry more energy at those ranges.




    tangosix.
     
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  14.  

  15. Both methods use C2 sight, with MPF you also have a set of range tables. But as Fallschirmjager has pointed out a bit of a waste of ammo (albeit a good hoot when I was at Warminster)

    Osta