The future of Small Arms and the reliability of New Technology

[Minuteman37]

After thinking about it for some time, I now dought that future small arms systems like gauss and lasers will ever be as reliable as conventional small arms, and caseless combustion based slug throwers will be the gold standard for reliability in small arms.

Anyone have reason to believe otherwise?

[mlangsdorf]

It isn't obvious that caseless ammo will ever be as reliable as cased ammo. Cases do a lot to simplify ammo handling, as well as acting as a heat sink while firing the gun. Not having to eject a case is nice, because it simplifies the gun's action and removes an opening where dirt can enter the gun, but it also complicates removing heat from the gun and removes an opening that simplifies cleaning and clearing jams.

Telescoped light cased rounds look interesting, as a reliable way to get more powder into a smaller and lighter bullet.

I also wouldn't discount gauss or lasers just yet. Modern designs are very crude prototypes based on a relatively simple understanding of the underlying physical laws. Using their performance to predict the performance of the mature version would be like saying that firearms would never replace bows and arrows because the early cannon locks weren't very good.

Our understanding of physics has been revised a couple of times between TL 3 and TL 8, and the fact that we don't have a solution for the observed behavior of subatomic particles that confirms to our understanding of general relativity means there's clearly a big gap somewhere. I don't know how that will get resolved, but when it does, I suspect that some things that we currently think impossible or at least very difficult will become possible.

Similarly, we know that the superconductor researchers don't really have a good model for the maximum temperature for superconduction. They've put forth a couple of limits in the past, which got broken by using different materials. Room temperature and ultra high temperature superconduction would solve a lot of our current problems with gauss or laser weapons (though by no means all of them) so there's plenty of opportunity for a TL10 society to consider lasers or gauss weapons more reliable than cased or caseless firearms.

[Anaraxes]

Many fewer moving parts in a coilgun / railgun. That has to help reliability. The whole legend of AK-47 reliability is based on less sensitivity to misalignment of those parts, and tolerance for getting dirt in the works -- which isn't an issue when you don't have works. Probably still have some mechanical bits for loading projectiles (unless someone comes up with a clever way to do that with magnetic fields as well), but it's a simpler design overall.

[weby]

As far as reliability goes, you have two separate things:
1) Reliability of the mechanisms in general
2) How resistant the thing is to real world use(ie mishandling).

The second is more relevant to military weapons, some relevance to hunting guns and self defense guns, least relevance to target shooting weapons.

The base reliability(#1) depends on things like the maturity of the technology(thus the experience of the designers), the manufacturing consistency/quality, materials quality and such.

The mishandling reliability depends on the general ruggedness(shock resistance), tolerances(tight tolerances tend to jam more easy but tend to help accuracy), how easy it is for foreign matter to get into action parts, how well the cooling works and so on.

Now the technologies when talking about auto/semiauto. All obviously likely have triggers in addition to the listed differences as a moving part.

#1 reliability:

Cased ammo: This has most moving parts as you need the ammo feed., cartridge ejection and firing pin movement both ways. The high reliability(in most cases) comes from weapon manufacturers having by now done fairly good job of understanding the ways things go.

Caseless ammo: This has less moving parts than cased as with the likely electrical ignition will only require the ammo feed as moving part eliminating a lot of moving parts. But compared to a cased ammo you have two problems: The cooling, as the ejected casing takes a lot of the heat away and the structural integrity of the round without the casing to hold it together.

Railguns: base reliability wise we have similar problems and moving part count as the caseless ammo gun(ie the ammo feed). But with current technology the problems of heat are even worse as the efficiency is so low.

Laser: If perfected these are likely the most reliable of all with no moving parts. Currently the energy requirement for a weapon grade laser is too high to be manportable and it generates huge amounts of heat so they require a lot off work to get there.

#2 reliability:
Cased ammo: These guns have a lot of open holes for dirt to get in so the reliability of even the most rugged guns is ultimately limited in things like combat situations where mud and dirt get in everywhere.

Caseless ammo: The elimination of the bolt removes the biggest and easiest way for the dirt to get in. So as long as the heat buildup is managed and the materials of the propellant are sturdy enough they will likely become more reliable than cased ammo. The heat buildup problem is something that is under great continuous research currently for electronics so will likely not be a long term problem. The mechanical durability of the ammunition requires specific research that is currently not being done due to no big country seeing the need for a caseless weapon, but should be just a chemical engineering problem and solvable with resources.

Railguns: The base reliability is as caseless ammo, except that the ammunition is sturdier, so there is not that problem. However the current "play" models would need to be ruggedised for military use so they can take the shocks of being banged around. Also the energy amounts will pose a higher problem than caseless ammo rifles for both cooling and carrying around.

Lasers: A fully mature ruggedised laser with good heat handling should be the most reliable of all the weapons as there are no holes you need to normally have open as even the barrel is sealed. But the cooling and basic ruggedness are problems that need to worked on.

So conclusion:
If all four things are eventually worked on enough to be mature technologies and the cooling problems are solved, the likely winner in reliability is laser, with railguns and caseless weapons taking second place and cased weapons far distant third.

[clu2415]

The US military’s prototypes for plastic-cased machine guns features a chamber that rotates to load a new round and push out the spent case. They have found that the plastic case contains the heat inside of it, transmitting less to the chamber. A brass case absorbs heat front he burning powder and carries some of that out of the weapon, but it is also conductive enough to pass that on to the chamber as well. Immediately after ejection, you can handle the outside of the plastic cases with bare hands. Since the barrel and chamber are separate parts, there isn’t as much heat moving between them and the rotating action of the chamber induces some airflow.

Word from the head of testing for the LSAT program.

More tidbits from the LSAT program: designing the cartridge case, belt, and firearm at the same time enabled them to greatly speed up the process of reloading. The 5.56 cased telescoped demonstrator weighs 10 pounds (compared to the FN Minimi’s 17 lbs) and the 7.62 demonstrator weighs 14 lbs (compared to various FN MAG models weighing 22-27 lbs). The weight savings come from designing parts using computer analysis to determine the exact strength necessary for a part to hold up under its stresses.

[AlexanderHowl]

Caseless ammunition needs heat absorbing filler within its structure to deal with the heat issue. Since most of the volume of ammunition contains filler rather than propellant, it is actually not that big of an issue, it is just finding a filler that will not compromise the structure and will avoid fouling the barrel. We actually have a lot of materials to work with (there are probably thousands of carbon chain molecules with adequate profiles), we just have to invest the money in finding them.

Ideally, the resulting caseless ammunition will contain a shell of heat absorbing material around a core of propellant. When the propellant ignites, the heat from the core would vaporize the shell and push the projectile down the barrel, leaving minimal material behind. Of course, you would then also have a problem with recoil with rapid fire, as no gases would escape to the sides to help stabilize machine guns and the like, but you cannot have everything.

[Anthony]

Originally Posted by Minuteman37

After thinking about it for some time, I now dought that future small arms systems like gauss and lasers will ever be as reliable as conventional small arms, and caseless combustion based slug throwers will be the gold standard for reliability in small arms.

In principle something solid state can be more reliable than something with multiple moving parts. A non-weapons-grade laser is actually far more reliable than any gun -- if you fire a gun continuously for an hour it's probably going to fail, plenty of lasers can go thousands of hours continuous use. The problem is always that you're operating at the cutting edge of performance when dealing with weapons.

[clu2415]

Originally Posted by AlexanderHowl

Of course, you would then also have a problem with recoil with rapid fire, as no gases would escape to the sides to help stabilize machine guns and the like, but you cannot have everything.

The only place “gases escape to help with recoil” is at the end of the barrel, through a muzzle brake or compensator. Nothing about caseless ammunition changes the use of a muzzle device.

Another advantage of the LSAT’s rotating chamber also with telescoped ammunition is that in a failure to fire, the next round simply pushes the unfired mess out of the chamber. And since there’s no reciprocating bolt slamming back and forth, recoil will be reduced somewhat.

[AlexanderHowl]

Escaping gases are often used to reduce felt recoil (http://www.shootingtimes.com/gunsmit...s-compensator/). While it is not often a concern in civilian weapons, it is often used it military weapons.

[evileeyore]

Originally Posted by AlexanderHowl

Escaping gases are often used to reduce felt recoil (http://www.shootingtimes.com/gunsmit...s-compensator/). While it is not often a concern in civilian weapons, it is often used it military weapons.

Those are all barrel mods. Again, nothing changes between cased and caseless in the regard.