[Bill_Rights]

(Note: I considered posting this thread on the Forum area "Firearms Research", but it seems that that area is devoted to old firearms.)

The US Army has made public the information that it has been researching for a number of years, and is seeking new research on, explosive ammo casings. [Where and how the Army publicized this is not important for this thread.]

The Army, and presumably the Navy/Marines, want the dismounted soldier to be able to carry more rounds of ammunition at the same weight or the same number of rounds at less weight, leaving more weight-carrying capacity for other things.

One way to do this would be to get rid of heavy brass cartridge casings and replace them with casings that are made of, essentially, propellant. Then when the round detonated, the casing would burn along with the dedicated propellant, thus reducing the amount of dedicated, internal propellant needed and, because the propellant-based casing would be made of not-metal, the overall size and weight of the cartridge could be reduced.

Is that cool, or what?

And, what if the primer could be replaced by something like a spark plug? Then the whole dang thing would vaporize and there would be nothing to extract. No more FTEs! Much, much faster rep rate in full-auto fire.

This whole concept, if proven workable, might be an equivalent advance as going from muzzle-loaders to cartridge-based firearms. Don't you think?

[Special_K]

The design has already been implemented and tried. The problem is that the brass case takes a lot of heat from the chamber with it when ejected. The designs built up a lot (A LOT) extra heat without that heat sink and things were not going so well.

http://en.wikipedia.org/wiki/Caseless_ammunition

[Palehorseman]

I think years ago even the Daisy Airgun company made .22 caseless ammo, and it didn't work out too well.

[Sunray]

HK tried caseless ammo, long ago. It didn't work. 1960's or '70's technology, as I recall.
Korean vintage 105mm recoiless rifles used an almost casing that would burn along with the propellant. I suspect the whole issue is a size and weight thing.
"...replaced by something like a spark plug?..." That's been done. Electrically fired 20mm Vulcan guns.

[Deus Machina]

Possible, and I think it will crop up... probably three or four generations of military tech later.

The heat is the big problem. Heat sink and--as a tinker, it just popped into my head--something like a short, wide piston to force a puff of air through the chamber when it cycles.

The primer can be integrated--priming compound covered with a binder. Still impact-fired (which I doubt will go away with any projectile rifle, for durability's sake) and would burn off with the propellant.

The big issue as far as Average Joe is concerned, is the utter lack of way to clear a stoppage--no casing means nothing for an extractor to yank on, and possibly no extractor at all. Even if it uses a metallic primer that needs to be extracted, try lodging a round into a sandy chamber and then pulling it back out without just ripping the primer off.

I do expect caseless ammo to catch on in the far future, if just because of a lack of material. And I expect it to hold on until energy weapons, at about the same time of the first fishing expedition to Europa.

Edit: More likely than caseless ammo would be a bullet with a hollow base containing a smaller amount of more potent powder. That would effectively solve both the weight-per-round problem, and the heat dissipation.Stoppages could be cleared by an extractor that must be manually engaged, and could hook into a driving band on the bullet, which in turn could be formed as a cannelure to hold the 'slug' of propellant in place.

Note to self: timestamp this, and check the nearest patent office.

[9teenEleven]

The other issue is the you generally need some kind of power source to load each round. IMO batteries in guns are bad juju.

[Jim Watson]

Sorry, Deus, almost all of that has been tried.
The distant ancestor of the Winchester, the Hunt-Jennings and Volcanics had hollow base bullets filled with powder. Since black powder is not very energetic, they were not very powerful. The only high energy compound known at the time was mercury fulminate and that would demolish the gun before enough could be used to drive the bullet.

Voere had a bolt action with bullet molded into a caseless propellant charge. There was a groove around the propellant cake and an extractor on the bolt head so you could unload without firing the shot in the chamber. A bolt action sporting rifle, it was not likely to overheat the chamber. It was electrically fired; two 15 v batteries claimed enough for 5000 shots.

[Nutgun]

If they do succeed you won't be shooting anything anymore. It will be controlled by the goverment for the government. There will eventually be nothing to reload and then we have no guns. Well we will have guns but nothing to shoot out of them.

Cleaver idea.... I'm sure it will be coming, well not coming to a gun store near you soon.

[anhedonic]

I wonder if it would be suitable to use a piezo effect trigger for ignition? No batteries to fail and decent voltage to cross a "spark gap" between the bolt face and the primer area of the cartridge. Caseless might require the development of a conductive propellant to complete the circuit, but I think a piezo system could be designed to satisfy reliability requirements.

Removing the mechanical components from the ignition would open up a lot of flexibility in placement of the trigger group (especially on bullpup designs!) and modularization of the unit could make replacement of the FCG as easy as pushing a retaining pin out/in.

Just thinking out loud while I drink this coffee...

[Justin]

In the early 1990s, Remington released an electrically -fired hunting rifle called the Etronix. I have no idea if the concept and product were sound or not, but a Google search will turn up a rant by a print magazine gun writer ranting about how all the jerks on the internet forums were responsible for the demise of the Etronix. It's a fairly hilarious read.

[FIVETWOSEVEN]

Post a link, I want to read it!

One thing about caseless ammo is that its not as durable and is more prone to getting wet than cased ammunition. The idea has merit and room to grow but it has these setbacks.

[Robert]

http://lmgtfy.com/?q=Demise+of+the+Etronix+Rifle

[SlamFire1]

HK tried caseless ammo, long ago. It didn't work. 1960's or '70's technology, as I recall.

Actually it did work. I heard that by the late 80's the Germans were just about to adopt case less ammunition, but then the Wall fell down, and the costs for reunification buried the idea.

http://www.65grendel.com/art002arammo.htmThe closest to adoption of all of the exotics was the caseless cartridge, in the form of the Heckler & Koch G11 rifle. It was actually about to be adopted by the German Army to replace the 7.62mm G3 (Germany never having adopted the 5.56mm NATO) when the Cold War ended and the Berlin Wall came down. Military re-equipment spending promptly halted. H&K were financially ruined by the cancellation of the G11 and fell into the hands of Royal Ordnance, where they have earned their keep by sorting out the long-running problems of the British Army's SA-80 rifle, but that’s another story\\\\\\\\u2026

[Artiz]

Trying to fix something that isn't broken, especially in the ammunition area, is pretty senseless... and of course, it doesn't work.

[Jim Watson]

Etronix electric primers are listed at $200 a thousand, none on hand at Midway.
Brass, bullets and load data are standard; so you could rebarrel an Etronix rifle to about any caliber.

The Kricotronic .22 of the 1980s fired standard ammo by putting many amps across the rim.

[TedP]

Metal Storm. Caseless, electronically fired. Ridiculously cool.

http://www.youtube.com/watch?v=d8hlj4EbdsE

[-v-]

Caseless ammo gives an instant weight savings on ammunition. A standard load of a .223 is say a 62 gr bullet over 23 or so gr of powder gives you a total projectile + propellant weight of 85gr. A loaded .223 round weighs markedly more than 85gr because of the casing. Cut that out, and you can have much more ammo with a lot less weight.

An equally interesting idea I saw was the use of a polymer case (as in everything but the rim was plastic). This also drastically drastically cut weight, and heat build-up, since the plastic serves as an excellent thermal insulator. I recall they were being sold in '05 or so, but I have not been able to find it since.

As for brass carrying a lot of heat out of the rifle: I doubt it. Brass is a very good thermal conductor, so most of the heat from the powder goes through the brass to the chamber. The ammount of cooling that brass provides is in the neighborhood of negligible and basically none.

[Jim Watson]

You ever had an ejected case down your collar? I think there is appreciable heat carried off by the brass.

[Shadow 7D]

The army was working on liquid propellant for the latest generation of artillery, but the crusader project was canned, according to what I read, the had everything about the system except the liquid propellant worked out.

[-v-]

Jim: Yes, there is considerable heat in that brass, you can't have heat flow without the medium heating up. The point being is brass is a very POOR insulator. Any heat from the burning/burnt powder passes through the brass to the receiver. (Heat can't flow from cold to hot, after all) The brass naturally heats up in this exchange.

Also, having a rather low specific heat (Jouls needed to raise 1gram of material 1 C), it takes relatively little energy to raise the temperature of the brass. Once its temperature is equal to that of the burning gases and/or the receiver walls, its stops absorbing any more energy. Any additional thermal energy flows through it to cooler parts of the firearm (receiver, chamber, etc.) Thus, while a freshly fired shell casing might feel quite hot, it has carried away a fairly small amount of thermal energy from the firearm, with most going into the hot gases, receiver, barrel, and air. Thats why after brass lays around for 10 seconds or so, its room temperature, while the receiver or chamber are still hot for a considerable time afterwards.

About the only time that brass provides any measure of cooling is when a fresh, cool, cartridge is chambered. Upon which, it also begins to heat up until it is at the same temperature as the chamber, or shortly, the same temperature as the burning propellant, which introduces yet more energy into the system.

[LaserSpot]

I think practical caseless ammo will be similar to Gyrojet rocket rounds, but with active steering. It will have pinpoint accuracy at any range.

“As a Recon man I liked the weapon just fine: light, quiet, low-maintenance, and a hell of a punch. It was not silent, not like the true silenced .22 Hi-standards we often carried. But it was quiet, made a sort of "Psssssst!" It sounded like air escaping from a truck tire, maybe a half-second long. I fired it in camp several times, demonstrating it, never got any attention at all.”

http://www.deathwind.com/review_2.htm
http://www.sturmgewehr.com/bhinton/Misc_Pics/GyroJetCartridge.jpg

[Bill_Rights]

Amazing. I think we THR folks have about covered it. Every issue has been touched on, maybe twice or three times.

In the RFP (request for proposals), the Army does acknowledge that there has been 50 years of effort put into case-less, propellant-cased and combustible-cased ammo. A lot has been learned.

I think the gist of the present-day drivers are 1) weight has just become an overwhelming concern, what with batteries and electronics a foot soldier might have to carry and 2) materials science and research just progress along and, who knows? - the answer-material might already have been discovered and we just haven't realized it yet.

Apparently, it is fairly common to use some version of case-less or combustible-cased ammo for larger calibers (30 mm and up). I guess that is because the gun itself is part of some vehicle system and the ammo supply can be kept dry and relatively controlled. The real, new challenge is to come up with small arms ammo (5.56 mm, 7.62 mm and 0.50 cal) that is lighter, since those are the man-carried calibers.

A huge issue we only touched on above is water permeation. Small arms ammo has to be usable even after dunking in water. If there is any water permeation, you'll get incomplete detonation, residue in the firing chamber, and build-up from there leading to failure-to-feed or bolt not in battery.

I think one place the Army is expecting breakthroughs is in coatings or films that are simultaneously waterproof but still combustible themselves. The issues of not having brass to expand and seal blow-by (Wikipedia article) and being able to extract a non-fired round will require some changes to the firearms. But I think (I could be wrong) the idea is to get this done sooner rather than later and get it into essentially the current generation of small arms, probably with some changes to bolt face and extractor form and function. Partly it is a matter of cost.

Yeh, I know. It is hard to believe, what with the 100s of billions the military spends every year, that cost is an issue. But the military lives under quite tight budget constraints.:uhoh: It is only the legislators in Washington that live under no budget restraint.:barf:

[WardenWolf]

Caseless ammo won't be practical for quite some time. The problem, as has been stated, is heat buildup. Given enough heat, the rounds can actually start to cook off, resulting in a mag dump. The heat problem would necessitate a cooling system that would eliminate any weight benefits. There are also significant fouling problems, as friction rubs off unburned propellant behind the projectile. And lastly, there's issues with the rate of burn causing insufficient acceleration.

[double bogey]

I think a system should just use projectiles: Load a bullet, inject a combustible mix in a chamber, spark it, repeat process. Develop a method to remove heat. Power weapon electrically like mini guns, use waste pressure to run generator to keep battery up. Maybe workable in a crew served weapon, may be too heavy for one person. I think with our technology this is very doable.

[Shadow 7D]

Look up the crusader project, then go look up liquid rockets, they have a nasty habit of going kaboom, and that would be very bad for what ever happens to be around when the whole thing goes, consider the valves have to take the force of the explosion and keep working, repeatedly.

Second, arty uses propellant bags, so it is caseless.

[heron]

I think a system should just use projectiles: Load a bullet, inject a combustible mix in a chamber, spark it, repeat process. This approach then requires some method of getting the bullet to seal tightly in the chamber; the fuel mix can't be allowed to escape past the bullet, and the bullet and chamber have to remain tightly sealed for some time . . . you might get the weapon charged and then have to pause for any number of reasons before firing. If the chamber gets too hot, the fuel might self-ignite; too cold and the fuel might condense in the chamber and fire unevenly. If it can leak at all, you could soon wind up with a squib. To me, that sounds like a really difficult thing to achieve.

You may decide to design the system so that the fuel intake becomes an integral part of the firing cycle (fuel doesn't enter until the trigger is pulled), but then, the fuel intake process becomes a factor in lock time.

[mondocomputerman]

"Trying to fix something that isn't broken, especially in the ammunition area, is pretty senseless... and of course, it doesn't work."

I guess we should have stuck to cap and ball. Or muzzleloaders. No need for an enclosed cartrige or any innovation for that matter...

[Avenger29]

I guess we should have stuck to cap and ball. Or muzzleloaders. No need for an enclosed cartrige or any innovation for that matter...

Except with muzzleloaders, cap and ball, and blackpowder metallic cartridges, there was lots and lots of reason for improving technology.

With smokeless cartridge arms, reliability is high, efficiency is pretty high, and durability is high. The system is also pretty simple. Talking about injecting air to cool stuff, electronic ignition, etc just makes stuff more complex and prone to failure.

Cartridges as they are today are pretty darn good. It would not make much sense to make a much more complex system just to get rid of brass casings.

[LaserSpot]

It sounds like the initial idea was to get rid of the brass case to save weight and cost, thereby allowing more bullets to be sprayed at the enemy. That's not the way we're heading now. Many new weapon systems are designed to reduce collateral damage and increase killing efficiency by take advantage of sensors, electronic intelligence, lasers, GPS, etc...

I think Gyrojet type ammo (it is caseless) is more practical because it solves a lot of problems. No extreme heat and pressure means that the launcher can be very light weight. It would also produce much less noise so you're more likely to hear the enemy and they're less likely to hear you. It would be guided so you don't need hundreds of rounds to ensure a kill.

Metal Storm is also a strong contender. Keep in mind that the army is starting to buy a lot of robots, not just for surveillance and bomb disposal either. Metal Storm type weapons would be maintenance free and ideal for future robots that are designed to sit in the bushes for weeks doing surveillance and ambush. It should work well in unmanned combat air vehicles too.

For close combat and self defense, I don't think fixed metallic ammunition will be replaced.



This is the kind of technology we'll be seeing:
Darpa, the Defense Department’s far-out research arm, announced a pair of contracts last Tuesday, to start designing a super, .50-caliber sniper rifle that fires guided bullets. Lockheed Martin received $12.3 million for the "Exacto," or Extreme Accuracy Tasked Ordnance, project, while Teledyne Scientific & Imaging got another $9.5 million.

http://www.wired.com/dangerroom/2008/11/what-if-a-snipe


This is actually in use! A cluster bomb deploys dozens of tank killing robots. Each robot uses a infrared sensors, lasers and image processors to identify tanks and other vehicles, then destroy them.
The BLU-108 Sensor Fuzed submunition contains four smart Skeet™ warheads equipped with dual-mode passive infrared and active laser sensors for target detection and engagement.

http://www.textrondefense.com/products/airlaunched/blu108.htm
http://www.youtube.com/watch?v=AKdFCsycYm8

[Bill_Rights]

LaserSpot,

Great observations and thanks for heads-up on those contract awards. I agree with most of your other points, too.

As for : A) the initial idea was to get rid of the brass case to save weight and cost, B) thereby allowing more bullets to be sprayed at the enemy.Your point "A" was exactly spot on. Your conclusion "B" is way off. The Army wants dis-mounted, mobile units to retain the same firepower as now but be able to walk on longer missions or carry more other gear. Less ammo weight trades to more water, food or just less physical exertion. OR trades to more batteries or other mission-specific "payload", if you permit me so to speak. Or some mixture of those two trades.

Or, the same everything else, just more shootable rounds of ammo.

We might be more careful than to say things like That's not the way we're heading now. If fact, where we're headed is where the next enemy drags us, if we can't outsmart him and have to rely on raw capability. On top of that, I think you know that within every military Service arm, there are multiple "constituencies". Evidently, the RFP for combustible-cased ammo is from that group within the Army that thinks there will always be a need for multi-soldier "boots on the ground" units walking into a hell-hole, clearing it, holding it, conducting operations from there a while, moving on, doing it again, getting back to base or extracted, etc. and doing it again. Snipers, armor, helicopters and artillary from over the horizon can't do everything, no matter what the capability of their weapons.

The whole point of lighter weight ammo is to get a person or team of humans onto a mission-determined patch of geography on the planet.

(Of course, vehicle and unmanned assets benefit from lighter weight too, but this RFP was clearly from the folks in the Army who think about human units on the ground).

[double bogey]

You may decide to design the system so that the fuel intake becomes an integral part of the firing cycle (fuel doesn't enter until the trigger is pulled), but then, the fuel intake process becomes a factor in lock time.


Heron, think diesel engine injector. As the trigger is pulled, fuel air mix is injected and spark happens. Of course I haven't figured out how to get the projectile in place yet, I'm sure there are smarter people than me in the munitions biz. Then there are other things, you wouldn't want to take a hit to your fuel tank in combat.

[Blakenzy]

Not so long ago I posted a thread asking why militaries do not use aluminum cases instead of brass, since it is not only a cheaper and currently available technology, but would go a looong way towards solving weight issues for infantry. I don't think anyone had a straight answer.

I think that in the end new cartridge systems are just low priority and not worth the institution's time. R&D, field testing, procurement and full replacement of what is currently in use is just to much trouble to go through and end up with a weapon of exact same practical effectiveness. Sure, it might be nice for the individual grunt to have caseless ammo, but it will not have a huge impact on what a rifle company will or will not be able to do. It is not a game changer. Now when energy weapons become feasible....

[heron]

you wouldn't want to take a hit to your fuel tank in combat. I hadn't thought about the fuel tank, and my first reaction was to think it would be another weight penalty of this system. I got this steam-punk vision of a big can on the soldier's back, like a fire-extinguisher, with a hose leading to the rifle -- and don't forget the carburetor!

Actually that isn't the case -- think of how many rounds you could get out of a can of butane lighter fuel. A few ounces, compared to maybe a couple of pounds of brass-cased ammo, and smaller as well. Give it titanium armor, and yes, hope it doesn't get hit.

[Mike OTDP]

Look up H&K G11. The Germans were about to adopt it, but the Berlin Wall came down and they needed the money for reunification.

[benEzra]

I hadn't thought about the fuel tank, and my first reaction was to think it would be another weight penalty of this system. I got this steam-punk vision of a big can on the soldier's back, like a fire-extinguisher, with a hose leading to the rifle -- and don't forget the carburetor!

Actually that isn't the case -- think of how many rounds you could get out of a can of butane lighter fuel. A few ounces, compared to maybe a couple of pounds of brass-cased ammo, and smaller as well. Give it titanium armor, and yes, hope it doesn't get hit.
The problem is, you need a tank of fuel AND a tank of oxidizer, AND you can't just inject an appropriate amount in the chamber and light it off like a potato gun. Atomized liquid propellants don't burn slowly enough at 1000+ degrees and 50,000+ psi to smoothly accelerate a projectile, so you need the capability to continuously inject more fuel and propellant into the chamber WHILE the combustion is ongoing and the projectile is accelerating in order to get performance anywhere near that of a conventional firearm.

Now, think of the injection system you need to safely inject fuel AND oxidizer against 50,000 psi backpressure with .9999 reliability. Then think about the power requirements. That's going to be a lot heavier than a few PMAG's and some web gear.

IIRC, the Crusader's prototype system used a gas piston system to do the heavy lifting with regard to the post-ignition injection, which helped with the weight and power requirements, but you then run into the problem of detonation in the propellant staging chamber (where the fuel and oxidizer must both be present to be forced into the firing chamber by the piston), and IIRC such detonation was one of the issues that led the Army to give up on the liquid propellant artillery thing and just go with conventional solid propellants.

[Manco]

Heron, think diesel engine injector. As the trigger is pulled, fuel air mix is injected and spark happens. Of course I haven't figured out how to get the projectile in place yet, I'm sure there are smarter people than me in the munitions biz.

In the end, it has to be as simple and effective overall as the current system, and thus far nobody has been able to figure out a better system. Much like evolution, technology growth in any particular field often happens in spurts depending on when there is a critical mass of new knowledge and a sufficient need for new developments. I think the fact that we're in the midst of rapid growth in the electronics and computing fields somehow gives people the expectation that similar growth should be taking place in all fields, but this is simply not the case. I know some people who look at their laptop computers, which are about as powerful as the massive multimillion-dollar supercomputers of 30 years ago, and think that we should be colonizing planets in other star systems by now because of "technology," but we cannot because we neither have the knowledge nor the technology to do so (and may NEVER have it, for all we know right now). We can, however, pretend to on our laptops in 3D video games rendered in real-time. :rolleyes:

Firearms have not changed much in the past century, and while I may well be wrong, I don't expect them to change much for perhaps another century, if not longer. Even the Halo series of video games still has humans using the same types of firearms we're using today, and that's because they're pretty close to ideal technologically and they work well.

Then there are other things, you wouldn't want to take a hit to your fuel tank in combat.

That's one reason to avoid liquid propellants. With current weapons, the same thing could happen if your ammo gets hit, but the solid propellants are probably safer in that case since they won't cling to people. By the way, the proposed system could be viewed as an autoloading development of the powder flask or horn, which in the context of personal arms could be considered less sophisticated or "advanced" than self-contained metallic cartridges, which are still state-of-the-art at present with no obvious knowledge or technology to replace them.

[-v-]

n the end, it has to be as simple and effective overall as the current system, and thus far nobody has been able to figure out a better system. Much like evolution, technology growth in any particular field often happens in spurts depending on when there is a critical mass of new knowledge and a sufficient need for new developments. I think the fact that we're in the midst of rapid growth in the electronics and computing fields somehow gives people the expectation that similar growth should be taking place in all fields, but this is simply not the case.

Almost. There also has to be a drive to do it. With the electronics industry, there is a vast consumer base with a lot of spare income that wants the newest, fastest, best, and most poweful lap-top so that they can post on Facebook about their new lap top and stream videos and "videos" from the internets at higher and higher resolutions.

In the consumer electronics field there exists now the ideal trifecta of ability, desire, and resources to push that technology through. Same with Medicine right now. Military small arms? Compared to the multi-trillion dollar electronics market, the consumer market for firearms and new technology simply does not exist. We, as gun owners, would rather get a new AR-15 (that is a 60 year old design at this point), then we are to shelf out money on a new, better, but un-tested firearm technology.

Same with major governments. The ability to make caselss ammo is there. The Germans already did it in the late 1980's. What is not there is the desire and consequently the resources (in raw $$$ terms) to make the push to a caseless weapons system.

If no one wants it, no one will shelf out the money to make it, even if it is quite feasible to be made.

[LaserSpot]

The whole point of lighter weight ammo is to get a person or team of humans onto a mission-determined patch of geography on the planet.I'm sure that was the idea, but now they have a new idea. Watch the video, it's really creepy: http://www.wired.com/dangerroom/2008/10/bigdog-20/

The Defense Advanced Research Projects Agency (DARPA) is seeking innovative solutions that will design, build, and test a legged vehicle capable of maneuvering robustly and nimbly among dismounted troops through complex terrain; carrying 400lb of equipment as well as sufficient fuel for 24 hours operation; sensing and negotiating terrain by autonomously selecting appropriate gaits, planning footfalls, and following a soldier through dynamic, cluttered environments; and operating quietly when required.

***

Sure, it might be nice for the individual grunt to have caseless ammo, but it will not have a huge impact on what a rifle company will or will not be able to do. It is not a game changer. Now when energy weapons become feasible....War is going to become even nastier when we start using megawatt lasers. When used on people, these will be like long-distance flame throwers; instant charred flesh. Even though you may not see the beam, anyone who looks at the guy or the truck getting fried will have seared retinas; permanently blinded. Here's a hundred-kilowatt laser in a C-130 hitting a truck:

Boeing Advanced Tactical Laser In Action: http://www.youtube.com/watch?v=qfmEUqmgsK4

***

Firearms have not changed much in the past century, and while I may well be wrong, I don't expect them to change much for perhaps another century, if not longer.Probably not, swords haven't changed much in the 800 years since firearms were invented. It took 600 years of product development before firearms were good enough to replace swords. Even then, the military held onto swords for another 100 years.

The answer also depends on how you define "firearm". Is a handheld weapon still a firearm if it fires little guided rockets? Particle beams? Death Rays?

Someday we may have handheld Laser-Induced Plasma Channel weapons that fire lightning bolts; these could replace firearms."Laser induced plasma channels (LIPC) combine three of the most awesome things modern science can produce: lasers, plasma, and giant electrical sparks. It's a method of controlling electrical discharges so that they actually hit a specified target, rather than jumping to whatever grounded object happens to be closest."

"The idea behind a laser induced plasma channel is to create a conductive path without the need to provide wires as a physical medium. Instead, powerful ultraviolet lasers can ionize a thin channel of air between the weapon and its target."

http://everything2.com/title/Laser+induced+plasma+channel

[benEzra]

Someday we may have handheld Laser-Induced Plasma Channel weapons that fire lightning bolts; these could replace firearms.
If you're a fan of the sci-fi Bolo series books by Keith Laumer and David Weber, the Hellbore (main battery weapon of a Bolo tank) was a laser-induced plasma channel weapon. The concept was that a gigawatt class laser heats the air and ionizes/evacuates the beam path, and then a millisecond later a several-megaton-per-second particle beam is fired down the evacuated path cleared by the laser. Neatly gets around the big disadvantage of particle beam weapons used in an atmosphere, which is atmospheric dispersion/energy dump.

[heron]

The problem is, you need a tank of fuel AND a tank of oxidizer, AND you can't just inject an appropriate amount in the chamber and light it off like a potato gun. Atomized liquid propellants don't burn slowly enough at 1000+ degrees and 50,000+ psi to smoothly accelerate a projectile, so you need the capability to continuously inject more fuel and propellant into the chamber WHILE the combustion is ongoing and the projectile is accelerating in order to get performance anywhere near that of a conventional firearm.There are any number of ways to get a controlled burn; I'm sure that problem can be solved, probably involving the choice of fuel components. Look into some of the things used as rocket fuel for some examples (including rubber hockey pucks!) There are quite a few pairs of chemicals that could serve; some of them react spontaneously without the need of an ignition system. The choices narrow with considerations for safe storage, stability and/or toxicity of the fuel components, and possible toxicity of the reaction's byproducts (it's a no-go if the smoke from the gun barrel can kill you). Note that these reactions might not all be classed as combustion.

Anyone for going back to plain old compressed air? It's been used successfully since at least the Civil War . . .

I have to say, I'm really enjoying this thread; it's one of the most stimulating I've seen in a long time.

[LaserSpot]

The problem is, you need a tank of fuel AND a tank of oxidizer, AND you can't just inject an appropriate amount in the chamber and light it off like a potato gun. Atomized liquid propellants don't burn slowly enough at 1000+ degrees and 50,000+ psi to smoothly accelerate a projectile, so you need the capability to continuously inject more fuel and propellant into the chamber WHILE the combustion is ongoing and the projectile is accelerating in order to get performance anywhere near that of a conventional firearm.At the State Fair, you can fire a BB machine gun. It's basically a hopper full of BBs that feeds into a barrel with compressed air going through it. How about firing a rocket through a Stellite lined barrel that's fed with a hopper full of Buckshot? It sounds like that's the kind of thing you're talking about; might be good for shooting down incoming mortars and RPGs, cheaper to reload than Metal Storm. I'm not sure what the fuel would be; Hydrazine & Nitric acid? I don't think I'd want to strap it on my back!

[benEzra]

I'm not sure what the fuel would be; Hydrazine & Nitric acid? I don't think I'd want to strap it on my back!
The Crusader experimental gun used a hydroxylammonium nitrate derivative as the fuel and nitric acid as the oxidizer, I believe. Definitely not something you'd want to carry on your back.

[Bill_Rights]

The Big Dog "pack mule" is great: (I actually think doggie boy did quite well on the ice!)I'm sure that was the idea, but now they have a new idea. Watch the video, it's really creepy: http://www.wired.com/dangerroom/2008/10/bigdog-20/ but it does not replace humans in the situation. Dull and dreary though it was, Gen. Patreus' campaign in Iraq of having foot units "walk, knock and talk" to Iraqi civilians (while camping in barns and one-night-commandeered housing at night) was probably one of the biggest things that turned the situation around in that theater. Big Dog/pack mule is not going to do that and may even be counter productive at the face-to-face meetings.

We got way OT with liquid-propellant small arms, as with "energy weapons" for foot soldiers. That's OK - good to think about. However, that is not what the Army is asking for solutions on today. I think the Army wants combustible-cased ammo that looks, feels and functions exactly like brass-cased ammo. Precisely why [B]is economics - the Army would like to convert the millions of existing small arms to fire the new ammo with nothing more than maybe a bolt change and an alternate but interchangable claw extractor. Ideally, this would be a field-change (or, at worst, an out-post armorer's job), so the same rifle could shoot either combust-case or brass-case, as needed. The requirement before you bid to this RFP is that the ballistics must be >= 10% better with combust-case than with present-day brass-case.

Speaking of economics, Manco and -v- were pretty much correct, except maybe swayed too much by the OT liquid-propellant and "energy weapons" small arms posts. Since the Army limited their request to combustible-cased ammo that is almost interchangable with brass-cased, and certainly uses the same basic long-gun platforms, most of these economic arguments don't directly apply. I think the ammo market for all the small arms in all branches of Service is a big enough market to drive technological innovation. HOWEVER, it is also true that the present Army RFP is somewhat of a "fishing trip", to get people to think about whether, in fact, the technology exists or can be quickly adapted to come up with reasonable combustible-cased ammo. If not, then OK; no contracts will be let against that RFP. And the Army will try again next year or in a few years. No harm, no foul.

[Manco]

Almost. There also has to be a drive to do it. With the electronics industry, there is a vast consumer base with a lot of spare income that wants the newest, fastest, best, and most poweful lap-top so that they can post on Facebook about their new lap top and stream videos and "videos" from the internets at higher and higher resolutions.

Well, if I had said "sufficient need and/or desire" then I would have covered it, but the part about knowledge--as in basic scientific and engineering knowledge--still applies. Humanity has enough knowledge of physics to push computers faster and faster for some time to come as long as there is money and impetus for R&D, but for example I doubt that the problems of interstellar travel will be so readily solved without major and unpredictable breakthroughs in our understanding of physics and the universe. As for the advancement of personal firearms, we've had ideas and partial solutions for a very long time now, but there are still some major technological hurdles in the way, mainly related to energy storage and utilization. Such barriers can more easily be overcome in large weapon systems, but personal weapons will remain a challenge for the foreseeable future.

In the consumer electronics field there exists now the ideal trifecta of ability, desire, and resources to push that technology through. Same with Medicine right now. Military small arms? Compared to the multi-trillion dollar electronics market, the consumer market for firearms and new technology simply does not exist. We, as gun owners, would rather get a new AR-15 (that is a 60 year old design at this point), then we are to shelf out money on a new, better, but un-tested firearm technology.

What you say is perfectly valid regarding even minor developments in firearm technology, but I was thinking more in terms of a shift away from explosively-propelled kinetic projectiles altogether.

Same with major governments. The ability to make caselss ammo is there. The Germans already did it in the late 1980's. What is not there is the desire and consequently the resources (in raw $$$ terms) to make the push to a caseless weapons system.

If no one wants it, no one will shelf out the money to make it, even if it is quite feasible to be made.

I'm not convinced that all of the issues had been worked out satisfactorily, and even if there were sufficient R&D drive to bring a workable system to the market (military and civilian), it's still just an incremental improvement over what we have now (I'd place its importance below that of smokeless powder, although we probably could have gotten along without that, too).

Probably not, swords haven't changed much in the 800 years since firearms were invented. It took 600 years of product development before firearms were good enough to replace swords. Even then, the military held onto swords for another 100 years.

The answer also depends on how you define "firearm". Is a handheld weapon still a firearm if it fires little guided rockets? Particle beams? Death Rays?

Personal weapons is what I generally have in mind, although developments in larger weapon systems is also interesting, of course.

Anyone for going back to plain old compressed air? It's been used successfully since at least the Civil War . . .

Is this type of system better overall than firearms? You go first. ;)

[LaserSpot]

the Army would like to convert the millions of existing small arms to fire the new ammo with nothing more than maybe a bolt change and an alternate but interchangable claw extractor.I don't think a bolt could be designed that would seal the chamber well enough and work with an existing barrel. Maybe they should go to a semi-caseless design that uses a metal and plastic head to hold the primer and create the chamber seal.



The Big Dog "pack mule" is great: (I actually think doggie boy did quite well on the ice!)Sorry to get off topic, but if you saw the Big Dog video (from post 38), this beta version is amusing to watch: http://www.youtube.com/watch?v=VXJZVZFRFJc

[Zak Smith]

Justin- that article was a hoot.

[stubbicatt]

Isn't the ammo for the Abrams "caseless?" Has a small ring of metal at the breech end with an extractor groove, I think?

[Manco]

Isn't the ammo for the Abrams "caseless?" Has a small ring of metal at the breech end with an extractor groove, I think?

It is very close as the rest of the case is consumed, and there are also some examples of electrically-primed ammunition used in cannons. With personal weapons, however, there are usually more drawbacks to these technologies than with large crew-served weapons (e.g. electrical power supply).

[Flame Red]

Didn't the big guns on the Iowa Class Battleships use powder bags - case-less ammo??

[CapnMac]

Yes, naval rifles are "separate loading" at about the 5-6" bore size.

There were dome variants of naval ammunition that operated like the British 25pdr, in that a case was loaded with powder bags, then loaded behind the round.

The case for this largely involved magazine design, as you can protect bags of powder differently than loaded, assembled rounds. The "gotcha" is time and manpower. If you need to be feeding ready-to-ram loads at 10 or 15 the minute you have a lot of guys below decks stuffing bags into cases. You also have a limit of either having two hoists per breech, or of compromising the case design. The fact that 5" and 6" weapons need to be Dual Purpose (either surface or aerial targets), the AA function needs uniform powder loads to better use ballistic computers for aiming.

Now, at an 8" or larger shell, the breech pressures and powder volumes just make a casing one more complication. Bundling the charges into silk bags (which will 99% combust) is simpler. There is a trick to it though, the rammer energy to seat the round is a great deal higher than for pushing bags of powder. Especially since that last bag has a priming compound base. This last was the final determination of what caused the explosion on Iowa; over-ramming the powder charge.

[Bill_Rights]

Yes, many big guns (crewed cannon, artillary, ship guns, etc.) use what is caseless ammo, in one form or another. Thanks, CapnMac, for the lesson on that.

LaserSpot said: I don't think a bolt could be designed that would seal the chamber well enough and work with an existing barrel. Maybe they should go to a semi-caseless design that uses a metal and plastic head to hold the primer and create the chamber seal. Early in this thread Special K was kind enough to point out http://en.wikipedia.org/wiki/Caseless_ammunition, which was pretty good and talked about rear-sealing of the firing chamber. It IS a problem. One thing the Wikipedia article said was: ...the French Chassepot solved the leaking breach problem with the addition of a rubber seal to the bolt.[8][9]

8.^ P.O. Ackley (1962). Handbook for Shooters & Reloaders vol I. Plaza Publishing. ISBN 978-9992948811.
9.^ See main article, Chassepot, for references
Also, Jim Watson remembered the Voere (German/Austrian) example. Voere had a bolt action with bullet molded into a caseless propellant charge. There was a groove around the propellant cake and an extractor on the bolt head so you could unload without firing the shot in the chamber. A bolt action sporting rifle, it was not likely to overheat the chamber. It was electrically fired; two 15 v batteries claimed enough for 5000 shots.
It would be interesting to know what solution Voere had for breach sealing.

I think it is a problem but not a fundamental problem.

[RSC]

"Isn't the ammo for the Abrams "caseless?" Has a small ring of metal at the breech end with an extractor groove, I think?"

Yep, the Rheinmetall Rh120 MBT Cannon uses ammo that has a partly selfcombustible casing (also used in the Leo II MBT). Most of the cartrige consists of a cardboad like material that goes up in smoke when fired. The bottom of the cartridge is metal (looks like an ashtray with a spike) and is the only part that is being ejected after the shot. As the highest cadence you can achieve with a human loader is about 1 shot every 3 to 5 seconds, you don't have to worry about heat buildup in the breach, actually the hydraulic recoil brakes are going to fail before the breach gets hot enough for a round to cook off by itself. Another fringe benefit was the ability to poke a meat thermometer through the casing into the round to measure the internal temperature of the round.
Having said that, the the heat management problem of the G11 was solved in the latest versions. I was part of the field trials back then and this gun was incredible, a true shooting machine. It looked like crap, but it made holes where you pointed it at and was extremly light compared to the G3.

[4thPointOfContact]

Just throwing this into the mix: ...
Anyone remember the Dardick gun?
http://s3.amazonaws.com/readers/2009/06/29/dardick_1.jpg

It utilized a revolving cylinder with three "tround" chambers. Tripling the number of chambers might alleviate some of the cook-off issues.
http://pds15.egloos.com/pds/200909/07/23/d0056023_4aa50fc75d116.jpg
http://upload.wikimedia.org/wikipedia/en/6/6d/Dardick_tround_pat_2865126_fig4.png

Using a cammed ejector to kick the round out sideways could solve the problems of no extractor grove and cook-off. (Finding a design that would resist chamber pressure might be challenging, though).

The real drawback to the Dardick system that I've seen is that
a) it feeds from an off-center location, one-third of a revolution from the firing position. [Edit: Actually, it could work from any position, even on top. The firing position could be at bottom dead center and still work.]
b) in order for the trounds to smoothly slip into a chamber there can't be a lip on the magazine, so holding the trounds in place is problematic.

Hmmm... combine tround technology with a horizontal (P90) magazine, then make the magazine seal by twisting closed the 'feed turret". To load, you insert the feed turret into the rifle and then swivel the magazine into place which opens the feed path??? Not too far out aside from having one extra moving piece on the magazine.

[Bill_Rights]

4thPoint,

I am not sure I follow all the details of the tround technology, but would it reduce weight carried by a foot soldier, for an equivalent firepower? That is the main point of the current Army RFP.

[Shadow 7D]

yeah when you look at the basic load of a soldier, with body armor you now add 30 pounds to what was traditionally carried, weight = reduced speed and range (exhaustion, less supplies) so every army wants to trim what they can to win battles, and 300 brass cases would be a start.

[Sunray]

"...Trying to fix something that isn't broken..." Happens all the time. That's why we have hordes of very similar cartridges. All of which the gun rag writers call the best thing since sliced bread. It's mostly a 'bring out new stuff or lose market share' thing.

[4thPointOfContact]

From what I've gathered about the tround technology ....

Caseless ammunition probably wasn't even on the radar screen when the tround was developed, but combining the two technologies might prove possible (with the resultant weight reduction). I can envision at least getting rid of most of the brass except perhaps for the primer itself. Get some 110% reliable electronic ignition and you could eliminate that as well.

It is suggested that it allows easier, less complicated feeding since the tround slips sideways into the chamber without regard to orientation, instead of having to be forced from the magazine into the chamber.

Weapon weight might also be reduced since there would be no heavy reciprocating bolt / bolt carrier, only a revolving cylinder.


It's all theoretical, but isn't that half the fun of trying to brainstorm solutions?