Mdthbs

I know I’m flirting with “Primarily Opinion Based” here, but I’m hoping there’s some established knowledge out there in the community that I might be completely oblivious to.

If you look at pretty much any science fiction setting, the design for any kind of ranged weapon is based on a modern gunpowder firearm. My issue is that these weapons are primarily designed around the requirements of the mechanism. Modern rifles and handguns are just about as ergonomically optimized as they can be, but the primary design considerations always start with the receiver/magazine/barrel assembly, and the next most important thing is recoil control.

So, the question is: If you have a solid-state kind of ranged weapon, directed energy or otherwise, where you can start with a clean slate on the shape and mass distribution, what would it look like if your PRIMARY design objective were to make it as easy as possible for a human being to aim intuitively and instinctively.

For the purposes of this exercise, assume the weapon isn’t going to be applying any force vectors itself (no recoil or vibration), but that we DO want to make the point of aim as stable as possible.

I feel like the right answer is probably:

• Three points of connection to the body at both hands and one shoulder (just
  like a modern firearm).


• Center of mass directly above the firing (rearward) hand, or directly above
  the line from the firing hand to the point of connection at the
  shoulder.


• Weapon’s axis of fire should be aligned as closely
  with and to the line made by an extended index finger from the
  firing hand. (e.g. using the weapon as a natural extension of the
  
  hand)

Are these the right assumptions though? Are there better and/or more stable ways to hold a ranged weapon to optimize hand-eye coordination? Am I missing any important ergonomic factors here?

EDIT: For this particular question, I'm looking for designs that passively align themselves most effectively to the body's natural hand-eye coordination, rather than something that (for example) relies on servomotors and measurement of the user's eye movements to mechanically align the aimpoint of the weapon to the eyeline of the user.

From OP: what would it look like if your PRIMARY design objective
were to make it as easy as possible for a human being to aim
intuitively and instinctively.

If you want instinctive, it would look like a rock. Humans would throw it.

https://www.smithsonianmag.com/smart-news/one-thing-humans-are-better-other-species-throwing-180949897/

The more we learn about animals, the less seems separates them from
us. Elephants are brilliant, dolphins are dastardly, apes can do
almost anything humans can. But there is at least one thing that does
set us apart: our ability to throw stuff.

Evolution has nothing to do with bows and arrows, or rifles, or catapults or cannons. But humans are instinctive and intuitive rock throwers. Our bodies and minds are evolved to throw rocks with precision. We have got culture and learning up the wazoo but if there is something we are hardwired to do as a species, it is to throw rocks. Even little kids are so much better at throwing than our ape cousins that the apes just look pathetic when they try to throw stuff. Humans are fearsomely lethal with thrown rocks.

A projectile that behaved like a thrown rock would be very easy for humans to use because thrown rocks are very easy for humans to use.

I think it should just be a pair of laser binoculars. If you can have a "clean slate" for pure accuracy and aiming purposes, I would make the weapon hit where you look through some binoculars. For example, in Zelda BOTW, there is a scope, similar to binoculars where you can aim it and click a button to leave a pin where you pointed. Do something similar, but have it be a death disc of destructive energy or something. If it is closer to your eyes, and it can pass through the same location you look through, then it will be very accurate. I know you wanted it more involved with the arms, but the most accurate way to shoot it would be to center it around your eyes. For stability, you can strap it around your head, and stabilize your head the way we know best, lay down. This takes the off center arm aspect and the aspect of an unsteady hand as well.

Aiming and maintaining your point of aim, as the OP states is paramount.

There are components to modern rifle design that impact a weapon's performance. You are right that some of it is based around the mechanism. Another large factor is barrel length, which has a large impact on accuracy. Longer barrel, better accuracy over distance. The third design aspect is use case. A design called a Bullpup compacts as much of the mechanism into the shoulder stock to bring the barrel back as close to your shoulder while leaving the trigger in a natural position for your hand. It gives you similar accuracy as a standard rifle, but given the weapon's shorter overall length you can use it easily in more confined areas like inside buildings.

Some of these aspects have additional benefits. Barrel length also impacts how you aim as well. With a very short barrel, like a pistol, very small movements alter the point of aim significantly. A longer barrel tends to be more stable on point of aim because small movements won't impact point of aim as much. I recently read an article comparing two pistols (I wish I could find it now) Both pistols had the same length of barrel. One was about an inch overall longer. This resulted in the slightly longer distance between front and rear sight creating a noticeable more accurate weapon.

All of this to say the human ergonomics are as important to your weapon design as the physical mechanisms of today's weapons.

Now, If I had the tech to create a non mechanical weapon with a directed energy beam, I would mount it to my shoulder with a stable gimbal mechanism with servos to quickly alter the point of aim. Link it digitally to glasses with a HUD, so one could aim with their eyes. The trigger mechanism would be in the glove. All of this to create a weapon that you just wear, doesn't impact movement, and will likely be far more accurate than any traditionally carried weapon. Think the three dot aiming mechanism in the movie Predator.

Just keep thinking about how it is to be used, and that may help you decide how to design it.

It's going to depend on the mission.

An infantry soldier who has to slog through some difficult terrain is going to want light weight, reliable, probably rapid fire. He wants something that he can carry 20 km through mud and brush and weeds, and have it fire without fail when the opposition shows up. Maybe he hasn't time to aim, he just wants to give the other side things to think about other than shooting him. Switch between single-shot and rapid-fire is good. A round that will reliably kill anything he hits is also good. But the rounds can't be too heavy because he has to carry a lot of them. Noise and smoke from the weapon may actually be desirable as psychological things.

A sniper wants distance, accuracy, and the ability to fire and not be detected. So minimal smoke, for example. And minimal muzzle flash. It would be nice if the weapon didn't weigh too much. But snipers can operate in teams, and move slowly through the area of the battle, so that's less important than for infantry. Maybe less noise is important, but maybe not. A very heavy round is not so bad because he may only carry a small number. Or he might stash a bunch in a convenient location. Maybe he has a second weapon for less accuracy-requiring situations. Maybe recoil isn't so important, as he might be able to brace the weapon.

Vehicle mounted military are going to have very different desires. They want a weapon that is gross overkill. When the guys in the armored transport with turret mounted guns show up, they want to be seen as things to run away from. You get into vehicle design very quickly. How much armor and where. How much engine. What sensors and what coms. Vehicles can also have a lot in the way of computer assist. They can have heads-up-displays and over-the-horizon assist from things like radar planes. They can mount a lot of stuff like ultraviolet and infrared cameras. And they can have tons of counter measures like smoke, loud speakers, special purpose rounds like tear gas, etc. They can do crazy stuff like putting their scope on a periscope, or launch a drone and use it to laser-paint a target.

A Smart Weapon

The issue isn't so much the shape of the weapon but how you target it. The weapon in theory doesn't even need to be held or even near the shooter.

The idea weapon then is a pair of glasses. It can track eye movement and lock onto what the shooter is looking at. A voice command, button press or even a thought could then trigger a smart gun with a tracking guided bullet to hit the target.

Suddenly it doesn't matter if it's a hand gun or an orbital cannon or even a cruise missile. You could even go hands free parrot gun like in Predator.

How about a tube (stock) with another tube (barrel) attacked, like a boomerang, or a pipe (tube)? It has a button near the thumb, or perhaps pressure sensors, so the user just holds the weapon with both hands, points their index finder, maybe braces on their body, points the weapon and squeezes their hand. You can edit the tube's weight however you like. The human eye can align a point at the end of a tube relatively well, that's how early humans calculated length and distance.