6 ms·

Someone a little better with aerodynamic drag computations could do a quick back-of-the-napkin to figure out the maximum range of something fired at sea-level g

Someone a little better with aerodynamic drag computations could do a quick back-of-the-napkin to figure out the maximum range of something fired at sea-level going Mach 3,4,5,6,etc. The biggest issue I see is just vaporizing the projectile on launch, so there would be an upper bound on muzzle velocity based on projectile material properties.

SEJeff 7y ago
But the US Military uses depleted uranium (the hardest material) for tank rounds, so they could make pretty hardy railgun projectiles.
- sharpneli 7y ago
  Not the hardest. Bit less than Tungsten so pretty hard but far from hardest. It is used because it is really really dense and hard enough. Perfect for piercing armor.
  - SEJeff 7y ago
    So perfect for a railgun projectile? :) What is the hardest man-made substance?
    - RantyDave 7y ago
      Artificial diamond? But it doesn't matter - you don't actually want something hard because you don't actually want it to go all the way through and out the other side. You want it to dump all that lovely kinetic energy into whatever it's hit.
      - SEJeff 7y ago
        Yeah, DU has an incendiary property along with a "self sharpening" property. It doesn't mushroom as much when used as a sabot round as tungsten. My platoon sergeant in the US Army was a former tanker and we learned all about it (I flew the Shadow 200 TUAV).
  - DuskStar 7y ago
    Depleted uranium also has a few other wonderful qualities - one is that it's self-sharpening, as the nose of the projectile will shear instead of deforming [0]. Another is that uranium burns in such situations, which means you get 'incendiary' for free. 0: https://en.wikipedia.org/wiki/Staballoy https://en.wikipedia.org/wiki/Staballoy
phreeza 7y ago
As long as the projectile travels fast enough that there is ablation, you can use the Newton approximation [1] to get a rough idea. Using densities for uranium and air, and a projectile length of 1m, that gives a range of 15km. Of course when the bullet slows down, that is significantly extended. [1] https://en.m.wikipedia.org/wiki/Impact_depth https://en.m.wikipedia.org/wiki/Impact_depth

SEJeff 7y ago

But the US Military uses depleted uranium (the hardest material) for tank rounds, so they could make pretty hardy railgun projectiles.

sharpneli 7y ago
Not the hardest. Bit less than Tungsten so pretty hard but far from hardest. It is used because it is really really dense and hard enough. Perfect for piercing armor.
- SEJeff 7y ago
  So perfect for a railgun projectile? :) What is the hardest man-made substance?
  - RantyDave 7y ago
    Artificial diamond? But it doesn't matter - you don't actually want something hard because you don't actually want it to go all the way through and out the other side. You want it to dump all that lovely kinetic energy into whatever it's hit.
    - SEJeff 7y ago
      Yeah, DU has an incendiary property along with a "self sharpening" property. It doesn't mushroom as much when used as a sabot round as tungsten. My platoon sergeant in the US Army was a former tanker and we learned all about it (I flew the Shadow 200 TUAV).
- DuskStar 7y ago
  Depleted uranium also has a few other wonderful qualities - one is that it's self-sharpening, as the nose of the projectile will shear instead of deforming [0]. Another is that uranium burns in such situations, which means you get 'incendiary' for free. 0: https://en.wikipedia.org/wiki/Staballoy https://en.wikipedia.org/wiki/Staballoy

phreeza 7y ago

As long as the projectile travels fast enough that there is ablation, you can use the Newton approximation [1] to get a rough idea. Using densities for uranium and air, and a projectile length of 1m, that gives a range of 15km. Of course when the bullet slows down, that is significantly extended. [1] https://en.m.wikipedia.org/wiki/Impact_depth https://en.m.wikipedia.org/wiki/Impact_depth