r/BeAmazed • u/Wooden-Journalist902 • Nov 15 '25

Technology Hypersonic railgun round goes through metal plates like they are made of paper.

Enable HLS to view with audio, or disable this notification

38.6k Upvotes

98% Upvoted

1.1k comments sorted by

View all comments

680

u/bit_pusher Nov 15 '25

I worked in a lab testing high velocity projectiles against armor plating. Both using a rail gun and a two stage light gas gun. I’m am super surprised, a little alarmed, they are doing this in the open and not into a target tank. Holy shrapnel Batman

10

u/VerStannen Nov 15 '25

What are the projectiles made out of?

I’d imagine something super hard and dense.

20

u/bit_pusher Nov 15 '25 edited Nov 15 '25

We were testing a lot of things, everything from aluminum to depleted uranium. What i found interesting is that projectile length had a huge effect on penetration depth, even without a dense projectile. This was all 20+ years ago, so I don't know the state of the art now.

10

u/Ok_Release231 Nov 15 '25

It would make sense that length would affect potential penetration depth.....

Just ask my wife and her boyfriend

0

u/Nothin_Means_Nothin Nov 15 '25

/r/wallstreetbets is leaking

2

u/Ok_Release231 Nov 15 '25

Huh? I've never even been to that sub. Do they also have a lot of wives with boyfriends?

2

u/CPTKickass Nov 15 '25

Isn’t basically just flying plasma after a certain point?

2

u/Level9TraumaCenter Nov 15 '25

If you're trying to deliver energy, your kinetic energy is a function of mass x velocity2 . Velocity has certain limits, while mass is a function of size.... and density. So you use denser projectiles, but some don't have good properties. Lead just "mushrooms" when it hits something hard. Osmium is ridiculously expensive. Uranium otoh is super dense, and self-sharpens as it penetrates, plus it's pyrophoric so when it penetrates the tank all that dust goes and burns.

But it's toxic and a huge environmental legacy; we'd prefer not to kill people decades later, so... how about tungsten? It's dense, super hard so it penetrates armor, not a big ecological toxin, safe to handle, and you can drive it hard without it flying apart, so let the propellant guys worry about how to improve that velocity thing, no limits.

Now that we kill tanks with relatively small and affordable shaped charges, we have less need to kill tanks with over-engineered uranium rounds anyway.

1

u/GherkinPie Nov 15 '25

I can imagine length helps as it will increase the projectile mass (so can obtain more kinetic energy) without increasing the size of the hole needed to punch through metal

2

u/bit_pusher Nov 15 '25

Even at the same mass, you will see increased penetration with length

1

u/Illustrious_Twist846 Nov 15 '25

I wonder if the relationship was purely linear.

Was there any time where increasing length very slightly lowered expected penetration, but then increasing beyond that increased it beyond predicted penetration again?

1

u/Itchy-Bedroom-6947 Nov 18 '25

Rigidity is a factor at a certain point. I would imagine so long as the projectile can maintain rigidity without and “wobble” or sinusoidal flexion in flight that the effects would be optimal. Watch an arrow fired in slow motion and note the wobble. But imagine that at tank scale and note you don’t want that flexion for a variety of reasons.

2

u/IronSkywalker Nov 15 '25

Dry weetabix

1

u/_Apatosaurus_ Nov 15 '25

What are the projectiles made out of?

Surprisingly, it's just paper towels and painters tape.