102

What a wonderfully macabre question! This calls for cited sources! First off, I'd like to point out that you are correct to notice the similarities between a grenade and a rifle round. Both have the same gross pattern: they set off some explosives near some metal that is going to be accelerated by the explosive. So if we start from that very simplified ...


55

So, you basically want a Harpoon Canon. A harpoon cannon is a whaling implement developed in the late 19th century and most used in the 20th century. It would be mounted on the bow of a whale catcher, where it could be easily aimed with a wide field of view at the target. Powered by black powder and later, smokeless powder, it would generally fire a large ...


49

Not very. Yes. Maybe. No. It depends. Would it fire? Yes. The powder charge would launch the cannonball towards the enemy. There might be problems with accuracy. And the cannon might burst, see the next point. Would it fire twice? Maybe. Depends on the strength of the walls, as you noted, and also on the presence or absence of flaws in the stone. Would it ...


41

The answer depends on a mighty host of factors, including how pointy your projectile needs to be. However, we can put together a pretty reasonable upper bound by looking at reentry vehicles. They are pretty much the fastest manmade things in the atmosphere. Apollo 10 came in at roughly 11km/s. The record fastest reentry vehicle was Stardust, which came in ...


38

Whether or not the non super blades will shatter is dependent not on your super blades but rather the process and materials used to create your standard fare swords. I will assume that your swords are steel for a couple reasons. Iron won't shatter, it's simply too soft. Some less common alloys and metals will shatter but in a world of swords (usually ...


37

In reading for this answer I was interested to see that a comparison of cannon metal strengths was published in the New York Times in 1861. This sort of thing was apparently considered to be of general interest. Which is very cool, and maybe a little sad - not for them, but for us. There are several different qualities which comprise the strength of a ...


27

The kinetic energy of a bullet (for non relativistic speeds) is given by the known formula $E_K = 1/2 m v^2$. For a velocity of $150 \ \text{km}/\text{s}$ you need about $100 \ \text{kg}$ to deliver 1 Kton ($4 \cdot 10^{12} \ \text J$) of kinetic energy. Apparently then you can double the delivered energy by strapping a nuke to the bullet. But... As in ...


26

At what velocities would the (aerodynamically shaped) projectile just burn up? Only a few km/s. Read up on the Sprint missile, which could reach Mach 10 in 5 seconds (which would be about 3.5km/s, though that slightly depends on the altitude it had reached at that point) which resulted in skin temperatures of 3400 degrees C and needed an ablative heat ...


22

The M67 grenade contains 180 g (6.5 oz) of composition B explosive. The amount of explosive in a gun or rifle is way less than that, just few grams. It follows that, close to the explosion, the damage of a grenade is dealt both from the fragments ejected in all the directions and from the shock-wave produced by the explosion. When an acoustic wave ...


19

Cool it may be, and to a degree you can do it, but it's a hair unrealistic. Might make good Manga, though. OK, for the record, bullets are cheap. So are arrows, bolts, spears, javelins, and just about anything else that's designed to fly through the air without spinning. Launchers for such objects are, for the most part, also cheap. Please keep this in ...


19

Combining the projectile directly with the air chamber and a single use valve is possible, (and exact sizing would depend on materials and valve design) but it is vastly inferior to a bulk storage tank design that is separate from your projectiles: Bulk tank storage means that you need 1-2 valves to fire potentially dozens of rounds at lethal velocities in ...


18

I won't expand on the math done by L.Dutch as it's correct and speaks for itself, however I would advise against the use of nukes in space for a few reasons: Cost Not only would you have to figure out the design aspects of the weapon, but you'd also be throwing expensive material away with each shot, if you had to choose in a war zone between throwing an ...


18

One key note is that you should never underestimate what the seeing impaired can infer with proper training. My mom for example is legally blind from toxoplasmosis; so, I'd imagine her vision is as bad if not worse than you are describing. Yet, she can beat most normally seeing people in a game of ping-pong despite not seeing the ball. People who only see ...


16

No. The energies involved here are just too great. First of all the "spear" would be gravitationally unstable, it would collapse upon itself and fold into a ball of metal, you couldn't make it strong enough. Even if you solve that problem, then in the collision with the planet a lot of energy is released. This would be enough to vapourise the spear and the ...


16

Because they are the most efficient way to deal damage to your specific target An (arguably) non-kinetic bombardment weapon would be an antimatter beam, which is a great opportunity to commit genocide..., no!!! cleanse heresy, no!!! strategically secure the target yes!!!. You did say that the planet should be captured intact, but there are many levels of ...


15

Would it actually fire? Yes, at least once. You might want to retreat to a safe distance for the test firing. Would it still be usable after firing? Depends if you calculated the right powder charge and if the flaws in the stone aren't too great. Would it be as effective as a metal cannon? No. Compared to traditional metals for making cannons like ...


15

This concept is extremely silly. It wouldn't work in any RPG setting remotely serious. That said, I love silly stuff. So let me chime in with my own ridiculous invention. A small, water-stained paper flyer finds its way to your hands. There is a strange, spiked cannon-like contraption on it that looks like the unholy cross between a mortar and a cover for ...


14

Very good, ubiquitous surveillance systems. If a KKV is coming at you at 0.99c from a couple light years away, it will take a couple years and a few days to hit you. That's orders of magnitude more time than you need to: Calculate the trajectory for an interceptor KKV of your own with an app running on a 2010's smartphone. Pick a proper, prebuilt counter ...


14

Ok, so first you design the ammo. Easiest would be to make something like ballistic knife. It's not only great projectile on it's own (because even if it won't open it's still a bullet) BUT the spring give it flexibility (try to drop a regular knife from 30 feet and see if it usable) needed for later use. The point of a ballistic knife is to LAUNCH a blade ...


14

Early bayonet. Simple as that. Just don't even bother solving the "being able to shoot without removing bayonet" problem. This fit down the barrel of the musket. Which means you could not fire the gun with the bayonet attached. This was a big pain on the battlefield, because you had to make the "gun to bayonet" transition while the enemy was ...


13

There are multiple, historical examples of artillery/mortars firing stone balls. Wikipedia has an entry (with photos, including some stone balls) showing only the biggest ones. So there's enough of a historical record that these weren't total death traps for the crews working them. I suspect there were many more of smaller caliber: https://en.wikipedia....


13

Space shotgun. Consider the payload from a railgun. It packs a wallop because of its velocity. The more massive it is the harder the wallop. A high mass projectile the size of a rocket would pack a very big wallop. It would also be energetically very costly to get it up to speed. But compared to space, even a rocket is small. And a very fast moving ...


13

Create - maybe. Use - no Let us look at the SS109 5.56mm x 45mm rifle cartridge. A complete round of ammunition (projectile, case, primer and propellant) has a mass of approximately 12 grams. The propellant mass is less than 2 grams, and does not completely fill the cartridge case. It would be trivial to double the propellant charge in a SS109 cartridge ...


13

The shockwave from a fragmentation grenade is negligible. A concussion grenade, which has few fragments and which is specialized to kill directly through explosive overpressure, has only a 2m kill radius (https://en.wikipedia.org/wiki/Grenade#High_Explosive_(Offensive). A fragmentation grenade has less explosives than that, and would deal very little direct ...


12

There are two ways to stop the bullet using a laser, vaporisation (which will cause the bullet to lose its momentum due to air resistance) and ablation (which blasts material off the surface to slow it down). For the purpose of this answer, we assume a bullet has a speed of 1000m/s and weighs 4 grams (5.56mmx45 NATO), and the bullet has to be stopped ...


12

You can use knives, spears or even harpoons because Kevlar is a material that is flexible, yet extremely strong. It stops bullets due to its extraordinary tensile strength. It does however have a low shear strength, which allows for cutting so if you don’t have ceramic and/or titanium plates in your vest then a knife, machete and or axe can cut right through ...


12

Slow-moving asteroid must originate in target system. Moving any object at a speed much slower than the speed of light from another system would take thousands of years and make war as we know it meaningless. So, an enemy must scout a proper object, likely in target system's Kuiper belt, and direct it towards the inner planet. This process should take ...


11

All magic aside, likelihood of a sword to break depends much more on the sword itself rather than opponent's sword. An "average eleventh century sword" is likely a Viking/Carolingian sword and it is made of steel of uneven quality. Steel (unlike pure iron) is more likely to break on impact, but it still not the same thing as shattering. For a particularly ...


11

I'm voting for the nukes, and not just because I'm a natural pyromaniac I think that many people spend their lives watching Star Trek and Star Wars and think that space battles are a lot like watching pre-1900 wars where ships of the line stood broadside and unloaded short-range light-damage cannon in bulk. In reality space battles will be much more like ...


10

Eleventh-century swords did shatter on each other. Let's turn to the Vikings here, whose "age" extended until 1066 AD. "A nick was a site from which damage could propagate across the blade resulting in the kind of failure seen in this historical blade (right). Clear signs of brittle fracture are visible. It could not have been a good situation for the ...


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