back to article New plastic telescope ammo machine gun is light as a rifle

The US Army has announced successful tests of a new, lightweight portable machine-gun which fires special plastic ammunition. The gun and ammo are so much lighter than current weapons and their brass-cased cartridges that some soldiers are suggesting that every infantryman could in future pack the sort of firepower reserved …

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Silver badge
Joke

There are gunners and gunners :)

"so much so that the gunner is at a decided disadvantage in a close-up gunfight where he needs to aim and shoot quickly while standing up."

Not if he can say: "If it bleeds, we can kill it". With heavy austrian accent of course.

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bleed?

I ain't got time to bleed!

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Anonymous Coward

You got time to duck?

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Go

lightweight bullets

Why not just make a lightweight plastic bullet that's compatible with current weapons.

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Headmaster

Simple: Energy of the round; the lighter it is the faster it has to go to have sufficient energy to penetrate the target, and it would slow down quicker.

Also accuracy is a problem at longer ranges as light bullets get blown about in the wind making them less accurate.

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I think Thomas 18's using the term "bullet"...

...loosely, and referring to the whole round, thus asking why we can't have a SA80/M16 compatible plastic-cased 5.56mm round. I rather suspect that the long narrow case would be susceptible to damage and distortion, and even were it feasible, the advantages of both the ammunition and weapon being lighter and less bulky and unwieldy would, by and large, be lost.

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Gold badge

So where does the heat go then?

The thing that has kept brass cased ammo around and the, theoretically vastly superior, caseless variety in the lab, is that the brass casing takes a lot of heat with it when it's ejected.

Now I can that the insulating plastic case keeps the heat out of the breech, a good thing, but that heat has to end up somewhere. Presumably more of it heads off down the barrel and out the business end, but that surely implies more heat in the barrel and associated barrel heating problems?

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Compared to friction and hot, high pressure gasses the case is not very relevent.

There is a 5.56 NATO (aka: .223 Remington ) cartrige that is "mostly" plastic, and it has been around for a few years. The base is still brass (about 6mm for the bolt/ejector) but the rest is a plastic, with a standard 69 - 70 grain* bullet up front.

They shoot exactly like regular 5.56 NATO ammo, they are just a little cheaper to make (less metal) and lighter to carry. The brass case of a 5.56mm cartridge makes up approx 30-50% of the total weight.

* "grain" there are 7000 to a lb (pound).

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Stop

AIUI

The brass ammo significantly cools the MG due to it taking a large proportion of the heat away. I doubt the new ammo creates significantly less heat, therefore the barrel and mechanism must be made of higher heat tolerance materials.

So I imagine it's expensive. You'd also show up like a beacon under IR.

Not to say I don't think this is the way to go but a) why jump when they're still making improvements eg caseless and b) it's not without its own drawbacks.

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Bronze badge

The heat in the breech is mostly from the combustion of the propellant, so whatever the case is made of, the heat has to flow through the case into the chamber wall. More thermal resistance from the plastic, less heat in the chamber wall.

And that may be why a plastic case is better than caseless.

Now, I understand the M249 has an easy-to-change barrel and so really is a machine gun. That feature is maybe more important that the effects of plastic ammunition, even if modern barrels can stand far more heat than those of WW2.

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xlq
Trollface

I don't think sustained means what you think it means.

"designed to be fired on full auto for sustained periods (though in short bursts only, or even its heavy barrel would soon fail due to overheating)"

So it's designed to be fired for sustained periods but only in short bursts? Intriguing.

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Pulling the trigger and emptying a mag is only done in movies. Not

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Bronze badge

Short bursts is standard for any machine gun. Better control of ammo usage. Even a Vickers didn't fire a 250-round belt as one single burst. Though a 10-gun company of Vickers guns did fire a million rounds in 12 hours.

I doubt this particular infernal machine is up to that standard

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Actually, not always the case

The US Army is now buying an M4A1 variant with a heavier barrel amongst other changes, in order to improve performance when troops have to "go cyclic" and fire automatic just about all the time. This occurred particularly in Wanat in 2008, where M4 barrels reportedly warped with the heat, causing the rifles to irretrievably jam

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Anonymous Coward

Bet the medics

are looking forward to pulling little bits of plastic out of the troops.

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Bronze badge

All the resources

of the US military at their disposal and they still use a string for test-firings, Mythbusters style.

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Coat

String Taxes

Oh they used those resources with this test, have no doubt of that. I'm sure they had to spend around $1000 to find the very bestest string in the whole wide world.

Sorry, have to find my wallet real quick in order to help pay for everythi-ah, I see they've alredy obtained it and emptied the contents for me, how thoughtfull...

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Silver badge
FAIL

I've just

built a brand new untested rifle, care to to pull the trigger for me while I stand 100m away?

I'm sure I made the locking mechanism correctly and it will only blow up slighty if I have'nt

Everyone testing a new weapon puts it in a test stand and ties the string around the trigger and waits for the bang or BANG or oh f*** back to the drawing board

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Caseless ammunition...

I notice that the article doesn't explore the question of exactly /why/ nobody adopted caseless rounds. Sure, caseless ammo is lighter, but it has some serious disadvantages compared to brass-cased ammo:

1. Nothing on the round itself protects the propellant from mechanical or water damage.

2. While you don't need a normal-operation ejection port for spent rounds, you still need a way to extract mis-fired rounds.

3. Caseless ammuntion makes the problem of cook-off worse, because there is no handy piece of brass to carry away some of the waste heat of firing, so it all goes into the chamber walls.

4. In a corollary to (3), the hot chamber walls take immediate effect on a caseless round, rather than after the small delay needed to heat up the brass case. Cook-off, therefore, tends to continue once it begins.

Plastic-cased ammunition, telescoped or not, will lack most of those disadvantages, provided the propellant remains sealed inside, as it is in traditional rounds.

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Eh? What

1. The G11 used a plasticised round that you could soak without ill effect. Plus, the rifle itself was largely watertight, and the ammunition supplied in prepacked sealed magazines .

2. The G11 managed fine, by allowing the failed round to be pushed down out of the way by the next round.

3. & 4. The G11 addressed cook-offs very successfully by utilising a very stable propellant whose ignition point was actually way above that of a standard round (after some earlier problems). The net effect was that the high ignition temmperature propellant rounds from the G11 were HARDER to cook off than standard 5.56mm (an M16 would cook off after about 60 rounds of automatic file, a G11 after about 90).

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Thumb Up

I was going to mention this as well. From what I understand, the reason the G11 was nothing more than a prototype was that the problem of "runaway" guns was too high a risk.

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Happy

Actually...

....the leading theory that I've come across is that it got killed off (effectively) by the wall coming down and the need to shave some off the defence budget , hence the adoption of the rather cheaper G36. As I say, cook-offs were largely eliminated, so the runaway thing wasn't much of a worry.

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Anonymous Coward

What killed the G11 is the same as will kill this baby: The entire supply chain for the regular guns and ammunition is carefully optimised to extract as much value as possible - and then some. Introducing something new upsets the flow and maybe creates opportunities for new people; thus not exactly what the regular cronies pay their damn senator for!!

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Anonymous Coward

Old idea in a new jacket

Ze Jermans already tried this, quite a while ago and indeed that was that G11, which didn't even need the jacket so that there wasn't even anything to expel left. Only just when they were ready to try it in the field, the wall fell down, they reunited, and to pay for that they cut lots of things including this. So, if the rednecks have been "working for some time on this", well, it got shelved a score or so years ago so it's about time they had something to show for their efforts.

<hat type="tin foil">So, who really did bring down the wall? The americans of course, because the G11 threatened the M16 and the 5.56x45. Why else? They stuck to that effigy even when it failed to work in dirty environments like, oh, Vietnam.</hat>

So, alright, you've made some "progress" and dug up half of an old idea. Now do it again in bullpup configuration and save some more weight and length. There's your lightweight carbine SAW. Do we have to tell you everything? Sheesh.

Perhaps not obvious to European readers, but lots of small arms related claims and decisions are actually based on personal opinions held to be more dear, perhaps, than religious beliefs, and the debates do have plenty of the flamefest nature. That goes for almost every aspect; rifle calibre (eg the .280 that landed by the wayside), like whether or not to use the bullpup configuration (there's more than one "discussion" out there full of "hard facts" that come down to "I don't like it"), and, well, you get the picture. Even after finally standardising on 9mm for sidearms (because everyone else already had done that a long, long time ago) there are still large swathes in the US military sticking to .45 ACP, basically on sentimental grounds. It's called "stopping power" but if you go look for hard, verifyable facts surrounding it, you'll find precious little in it, certainly compared to the volume of other stuff in the debates. <troll>So, why cling to 5.56 when you have alternatives with more stopping power but insist on worshiping the 1911 and .45 ACP, eh? We have learned a thing or two in the past century, even if you haven't.</troll>

I don't really care much except that it is indeed stiffling innovation something fierce. And, well, perhaps not even there. We can already kill each other dead so much that if we'd put our minds to it there wouldn't even be a planet left. As you were, then.

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Re: Old Idea in a new jacket

<troll>So, why cling to 5.56 when you have alternatives with more stopping power but insist on worshiping the 1911 and .45 ACP, eh? We have learned a thing or two in the past century, even if you haven't.</troll>

Military small arms has ALWAYS been the most conservative part of arms procurement, and often the reason is simply economic; there are literally billions of rounds of 5.56x45NATO knocking around the various western armies and the rifles to go with them. It took NATO nearly 25 years to standardise on 5.56mm in the first place, and the bigger the pool of troops that need re-equipping and training, the more resistance to change there is (its one of the reasons the British Army was saddled with .303 Lee-insert model here rifles for 60 years; don't believe the cod about what great rifles they were - the MOD had a mountain of ammo to get through*).

*I know they were good rifles in isolation, but British troops shouldn't have been using bolt-action rifles as late as the Korean war.

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Anonymous Coward

Of course.

Meaning that as an enthousiast or so, you shouldn't rely on the military to pick the bestest kit, except as an indication of what ought to be squaddie proof and can shoot widely available ammo. Remains the quibble that picking the 5.56x45 itself for standardisation was less than entirely rational. Though, looking forward, now with a couple wars going on and another on the horizon, shooting out the old stuff to make room for something new suddenly is an interesting option, especially if the new stuff is cheaper and can claim to be better in some other way too.

So the timing of this is a lot better than for the poor guys at H&K R&D back in the 90s.

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Anonymous Coward

Stability of Plastic

At High (viz Saudi Desert in Summer) or Low (viz Alaska in winter) temperatures is going to be a problem

At one end, it gets a tad soft and it expands.

At the other, it gets a tad brittle.

While this beast might work somewhere in the middle, I'd rather not be using this where the US army is currently deployed. The issue of a round jamming up the spout will take on whole new meaning.

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Boffin

RE: Stability of Plastic

I'm also curious as to whether there is any plastic residue in the chamber after sustained firing with plastic-cased rounds. Caseless ammo is potentially even worse - to make it waterproof, solid and stable, other chemicals are added to the powder mix to bond it together, and they were reputedly a problem with fouling for the G11.

I'm also wondering where does this leave the 6.8mm SPC round which is supposedly so close to US Special Forces' hearts. I presume a rifle/LMG made to chamber the new 5.56mm plastic-cased rounds could be rebarelled to fire one with plastic-cased, telescoped 6.8mm SPC....?

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Anonymous Coward

Surely if all the soldiers in a squad are carrying LMGs it will be a lot more wasted ammo?

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The problem wont be wasted ammo, it will be running out of ammo. There's only so much a soldier on foot can carry, and you use up ammo surprisingly quickly even with a bolt action rifle. Not a problem in a defensive fight, where you can be dug in with a stack of ammo boxes, but on patrol I'd be seriously worried about getting into a firefight and not being able to cover a retreat because I've expended my entire ammo in the first minute or so of an encounter.

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Angel

Perverse?

That they are not rolling out these rifles to infantry divisions en masse as opposed to spending the money on shinier planes and subs? No not really.

A) The makers of the shiny stuff throw more dosh at our corrupt politicians and military types.

B) I bet this rifle (and the ammo) and anything else of this vein is really expensive. Possibly fine for special forces, but horrifically expensive when you start ordering hundreds of thousands of them.

C) Soldiers break things. Frequently. Making your rifle of solid metal (and heavy) makes it last longer and easier to fix. Light, weaker things turn out to be more unreliable.

D) The physics behind brass cases has been around for a long time and they are tough enough to get loaded into rifles without taking damage and for the bullet to remain accurate as it leaves the barrel. Plastic is a whole different ballgame. I can't see the vids at work, but did anyone mention anything about muzzle velocity, bullet rotation and accuracy? If not, any military person will ask as these are_kind_of_important!

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Bronze badge
Terminator

glocks

they made a lot of noise about C with the glocks came out too.

Now 3/4 of law enforcement use em.

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Anonymous Coward

Is there a shark mounted frikkin Laser option yet?

No thanks then.

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heat?

There are other advantages: the new LMG's novel rotating chamber (shown in action in the vid below) doesn't heat up as an M249's does

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Bronze badge

what could possibly go wrong?

The old style rifles are so primitive they can be made and repaired with hand tools in a village in the Khyber pass and cartridges reloaded endlessly. The cold war has meant there's a huge supply of the main calibres sitting in sheds. Why not replace all that with something new and allow soldiers to fire more rounds per individual at the same number of targets?

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You might be able to repair an AK-47 or decent carbine with simple tools, but they still jam up easily enough in wet or dusty conditions. Not convinced about this new LMG with it's spinning chamber though - it's the barrel I'd be most concerned about when it comes to heat, as that's the component that has to be switched after only a few hundred rounds of rapid firing. An important consideration that's often overlooked - particularly in films, where I've never seen a barrel change.

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Wasn't there a barrel change

... in Saving Private Ryan. During the scene where they're going against the gunner's nest?

Maybe not, it's been a while...

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Not watched Shaving Ryan's Privates - my grandfather, who was dropped as a para on Pegasus bridge, watched it and told me it was wildly inaccurate. For starters, it featured allied soldiers aiming their weapons and firing single shots or controlled bursts - in reality they fired wildly, expending the whole magazine in one go with automatic weapons. Amongst my grandfather's colleagues, the Yanks were particularly derided as poorly trained, poorly lead and ill disciplined. He said that if it wasn't for air superiority, the allies would have never got off the beaches at Normandy.

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*shrugs* Personally, I'd always assumed the reason that rifle squads/sections don't have a half a dozen machineguns each was basically cost more than weight. This wouldn't change that.

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Boffin

There's one other factor with plastic cases...

... and that's pressure from the burning propellant. *lots* of pressure. And yes, heat dissipation is also a factor- ask anyone who's been pelted with freshly fired brass at a shooting range. :)

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Stop

"the current M249 (a version of which is also used by British troops)"

Er, no. They're both versions of Belgium's FN MAG: in fact the British Army adopted the MAG-based L7 GPMG in the 1950s to replace the ageing (though still well-liked) Vickers gun, whereas it's only recently that the Americans finally adopted a MAG variant as the M249 after decades of stubbornly sticking with their bloody awful M60. We're all used to the "American military is awesome" rhetoric here, but it's a bit misleading to imply that the L7 GPMG is a version of the American gun.

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Don't forget

The M60 is a derivative of the MG42, invented by ze Germans in WWII.

I see the ammo vs weapon issue in the same light as inkjet printers and ink manufacturers!!!

Over the lifetime of a military weapon (esp in the field) they will expend many times their purchase value in ammunition.

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Headmaster

Almost ...

The FN MAG is an older gun, dating back to the 1950s and used by almost everyone. This was taken into service as the GPMG by the UK many years ago. Eventually the US saw the light and ditched the M60 in favour of the FN MAG, which they called the M240.

The FN Minimi dates to the 70s. It was adopted by the US in the early 80s, and only taken into service by the UK in the last few years, as a UOR (Urgent Operational Requirement) for Iraq/Afghanistan.

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Facepalm

@Bumpy Cat

Right you are, I hadn't quite grasped that all important M240/M249 difference, so a big fail to me in that regard. Darn numbers, why can't they give them nice-sounding names instead!

So my point still stands, but it'd be nice if I could make it without introducing a gaffe of my own just for once... :(

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Unhappy

Found another article quoting an ARDEC engineer:

Re heat / cook-offs:

The rotating-chamber design provides better heat management. Combined with the insulating properties of the plastic ammo cases the LSAT LMG has potential to decrease the possibility of a cook-off or eliminate them altogether

Re accuracy / lethality:

The cased telescoped ammo still provides the same muzzle velocity, range and accuracy as the brass-cased ammo. We’re not sacrificing lethality for weight. The plastic case does the same job.

Another significant feature is the long-stroke, soft-recoil design, which provides a noticeable reduction in felt recoil over the current SAW. This significantly increases control, thus providing the shooter the ability to put more rounds on target and making the weapon much easier to fire from the standing position as a result of decreased muzzle rise.

Also, according to never-knowingly-accurate Wikipedia:

- the caseless version of the gun has been in test since 2008

- the caseless weapon is 1% heavier than the cased as it requires additional seals in the breach

- pricing is expected to be equivalent to the current SAW

- they're also considering other 'more lethal' (read: larger) calibres (makes sense)

So all good. Unfortunately, no-one's expecting either of these to be adopted any time soon ..

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Gold badge
Joke

Note the state of the art remote weapons activation at 00:30

Worth the viewing all on its own.

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Joke

The Rest of the Story...

And when it's not being used in combat, it doubles as an awesome Pez dispenser.

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Anonymous Coward

Re: Old idea in a new jacket

"<troll>So, why cling to 5.56 when you have alternatives with more stopping power but insist on worshiping the 1911 and .45 ACP, eh? We have learned a thing or two in the past century, even if you haven't.</troll>"

You mean like the 6.5mm Grendel, with its flatter trajectory, better range, and better accuracy that the puny 5.56? We have learned a thing or two ourselves, even while you Europeans look down your noses and say "We could have made better, if we wanted to."

http://en.wikipedia.org/wiki/6.5_mm_Grendel

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Anonymous Coward

You just had to bite, didn't you

I know about the grendel and I also know that's it doesn't come in boxes stamped "NATO". Now read up and take note of the "NATO standardisation" section: http://en.wikipedia.org/wiki/EM-2_rifle

The point stands.

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Facepalm

The irony, it burns

The US dictated both the 7.62 and the 5.56 rounds to NATO, the first in the 50s and the second in the 60s/70s. "Us Europeans", especially the British, were very keen on the old .280 round, which both in tactics and ballistics is quite close to ... the 6.5 Grendel.

So you've just re-invented something that we developed 50 years ago, and are ranting at us for adopting something that you forced us to adopt. I guess it's true - Americans don't understand irony.

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