XM-307/312

Discussion in 'Weapons, Equipment & Rations' started by The_Cheat, Jan 14, 2008.

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  1. http://www.globalsecurity.org/military/systems/ground/m307.htm
    http://www.globalsecurity.org/military/systems/ground/m312.htm

    Ok just seen this on TV and it looks like the nuts! I'm a bit worried about the whole digital aspect of the grenade round but seeing it on tv's changed my mind.

    Two guys changed it from the 307 into a 312 in 1.43 seconds. What do you arrsers think? Is there a need for a weapon that can change roles like this? Thinking about Helmand and the old Platoon houses / District centers I can see the usefulness.

    T C
     
  2. XM-307 is a deeply flawed concept as the airburst grenade is only the size of a large marble, i.e. it is going to be more or less ineffective unless you pretty much hit the target smack on. I've seen a demo video where they demonstrated the effectiveness of the system by bursting balloons! The fancy electronic airburst fuze is also going to be hugely expensive in comparison to ordinary mechanically fuzed grenades. IMHO the UK made a sound decision in going for the 40mm H&K GMG - which gives a much bigger bang and cheaper ammo too.

    On the other hand the XM-312 may prove to be a sound weapon. However, I would like to see some evidence that its low rate of fire would make it an effective replacement for the classic M2 HMG - only 76 years young this year!
     
  3. Ah, I thought it was the same caliber as the same caliber as the 40mm H&K that we've got.

    The main plus I could see would be that if you ended up being in a fixed position you could change one of your .50 Cals into the grenade type thingy. I was a bit dubious about the round it fired, but did like the airburst idea.

    T C
     
  4. With reference to the M4 thread, the US does tend to go for "we want a 100% improvement in effectiveness, or it isn't worth changing what we've got" approach. Since that meant an effective range of 600m (as opposed to the M16 and 300m) they could either teach every soldier to point the rifle twice as accurately, or come up with a "technical solution".

    Now, that either means some cunning way of removing windage and range errors, so that you just put the pointer on the target (in effect, shrinking the Chieftain IFCS into something that fits on top of a rifle) or by making the target twice as big (by making near misses count).

    With their XM29 OICW, they tried to do both - that 25mm round is designed to go off within a foot or so of the target, assuming it doesn't actually hit. It may be a marble, but if you're willing to wrap a marble of PE4 with some notched wire and set it off a foot from your face, arms, or legs, you're a braver man than me... with the added bonus that the opposition need overhead cover, because you can set the sight to aim off for "just over that wall that I'm aiming at" or "just through that window I'm aiming at" instead of "inside or right next to that bloke I'm aiming at".

    Of course, the XM29 failed to meet its weight targets, so it got canned, but the ammunition was always going to be part of the OCSW.

    Anyway, back to the M307 - the problem AIUI with the ammo is that it could be set off at a predetermined range. Which means that you've got quite a small beaten zone (like arty) because it's not going to have as flat a trajectory, rather than a long thin one (like an MG, which you get when you convert it to M312). It's almost a belt-fed light mortar (smaller bangs, but many more of them, much more accurately delivered, very low angle only)

    I can see it being used as "horses for courses" - you use it according to the effect you wish to create. The advantage is that you're only carrying one damn great tripod, breech, and sight set around for two different effects - the disadvantage is that you can only use one at a time......
     
  5. From what I understand the grenade can be either detonated on impactor set to go off '1 Meter past the target'. There's a built in ranger finder, so if the wall is 200m away you can dial that in, aim over the wall and the round well detonate at 201m. That sounds great to me! I saw a program with it on and they were putting it through windows and it looked very good at that.

    Also, it's a 40mm round, surely that warhead's going to be bigger than a marble? Or was that a euphemism? Because it has to fit in all the extra fuze stuff I thought it would probably end up with about 3/4 to 3/5 of the explosive as a normal 40mm round from a UGL.

    It's coming into service soon any way so lets watch youtube and see how well it works!

    T C
     
  6. Saw that episode of Future Weapons as well (is it me or the guy that presents it a bit, well, 'dodgy'?) - the grenade launcher is 25mm.

    The demonstration did what it was supposed to do - where's the surprise in that? Demos are there to sell it to people! :)
    As for its effectiveness in a real-life situation, I'll leave that up to more qualified members of this forum - personally I think that if you gave it a British squaddie they'd break it within five minutes! (although the Shiny Kit Syndrome reading on this is off the scale!!) :D
     
  7. 'Designed to' is right. The fancy fire control system doesn't account for wind induced errors, which can be substantial with a low velocity projectile. I would have thought that a long range rifle shot like yourself would know that better than most people!

    Fair point, but I should have clarified my point by saying that a 25mm grenade will be pretty ineffective against a soldier wearing a helmet and body armour. Now I know that the Yanks say that they have never actually had to fight an enemy wearing body armour, but is that always going to be the case?
     
  8. I'm liking it less and less now... shame really, because it looks nice!

    And yeah, I did see it on Future warrior or something. The Ex-Navy seal guy can be bit a strange...

    T C
     
  9. Mr Happy

    Mr Happy LE Moderator

    I've liked the idea for some years. Its not necessary to kill the bad guy after all.

    Whats wrong with just firing a 50cal round instead, that'll pen' most cover and scare the bejesus out of the bad guy if they're not blown apart?
     
  10. Cutaway

    Cutaway LE Reviewer

    But it probably won't penetrate most cover unfortunately.
    The L2A2 contains about 170 g of RDX/TNT but has notoriously shite penetration, the 'new' L109A1 EPG does better with slightly less HE, but still considerably more than can be packed into a 50 cal head.

    Unless or until the boffins can design a micro-nuke to fit in a ½" tapered cylinder, the 'fifty cal AP gren' will remain a paper tiger.
     
  11. So, get a ballistic computer built into the sight? I seem to recall a project that was investigating detecting brownian motion (dust particles moving through the beam) in a laser rangefinder, so that you could get an estimate of wind speed all the way to the target.

    Certainly, if you ignore the "k3wl gun" hype, you'll see that CheyTac build a ballistic computer designed for snipers:
    http://en.wikipedia.org/wiki/CheyTac_Intervention

    http://www.cheytac.com/ABCPage.html

    Tart it up a bit, and bolt it on top of the gun. Oh, and as for wind, you could always fire a burst and observe strike, should be easier with a belt feed of things that go boom. Call me a bluff old traditionalist :)

    Long range? 50m, that's as far as I go. With occasional dalliances in "the dark side" (100yds).

    But then, it is only 0.22RF, the bull is 10mm across, and the swirling winds you get even in a walled range will push you a centimeter or two. Did I mention the target is the same size in the standing unsupported position?
     
  12. Mr Happy

    Mr Happy LE Moderator

    Cuts, you misunderstand, I mean 50cal bullet, you know, like the thing that comes out of, oh, say, a 50cal, not a 50cal explosive tipped grenade.
     
  13. Cutaway

    Cutaway LE Reviewer

    Ah, my apologies.
    Disregard my last then. :D


    If you really want penetration from the BMG, try some of these:
    [​IMG]
    The 7.7 tungsten penetrator goes through an awful lot of concrete.


    I must admit to never having seen a belt like the one pictured, everything we received was linked 1SLAP:1SLAP-T - (1BIT if you like.)

    [​IMG]
     
  14. Mr Happy

    Mr Happy LE Moderator

    remember, all ammo must be used up by the end of the bush administrations tenure...