4 ms·

Musket balls are actually horribly inaccurate. Whatever spin that gets imparted on it tends to cause it to fly in a direction due to the Magnus Effect. If you d

by chipsa 5y ago

Musket balls are actually horribly inaccurate. Whatever spin that gets imparted on it tends to cause it to fly in a direction due to the Magnus Effect. If you don't impart a known amount of spin and direction of spin, the projectile will get deflected a variable amount in a variable direction. This is why paintballs and airsoft have hop-up: it provide a consistent amount and direction of spin, in a favorable direction to increase range. Why do musket balls have spin? Because there's space between the ball and the barrel, and as the ball moves down the barrel, in bounces in the space, and every time it hits the wall of the barrel, it ends up getting a bit of spin from that contact.

graderjs 5y ago
Curious...going big picture about ballistic projectiles for a moment...what about a hollow-all-the-way-through projectile shaped like a jet engine air intake with "rifling" on the inner side to turn airflow, spiraling the incoming air from the wider "mouth" of the bullet toward a tiny "nozzle" at the rear of the bullet, through which this air is expelled. I'm not physicist-enough to know if this will do anything, but is this in anyway a plausible idea...or just terrible? Happy to learn.
- chipsa 5y ago
  I think what you're effectively looking at is a rifled (Foster) slug. Turns out the rifling on the slug doesn't do much. The majority of the stabilizing effect on a Foster slug is from the fact that the center of gravity is well ahead of the center of pressure. Having an actual hollow all the way through the slug with rifling would probably have increased air resistance compared to having the rifling on the outside, while rifling on the outside would have better ability to apply torque to the projectile. So knowing that rifling on the outside doesn't work well, we can estimate rifling on the inside would do even worse.
  - graderjs 5y ago
    Awesome, thanks! Well was worth a try.. Heh

by chipsa 5y ago

graderjs 5y ago

Curious...going big picture about ballistic projectiles for a moment...what about a hollow-all-the-way-through projectile shaped like a jet engine air intake with "rifling" on the inner side to turn airflow, spiraling the incoming air from the wider "mouth" of the bullet toward a tiny "nozzle" at the rear of the bullet, through which this air is expelled. I'm not physicist-enough to know if this will do anything, but is this in anyway a plausible idea...or just terrible? Happy to learn.

chipsa 5y ago
I think what you're effectively looking at is a rifled (Foster) slug. Turns out the rifling on the slug doesn't do much. The majority of the stabilizing effect on a Foster slug is from the fact that the center of gravity is well ahead of the center of pressure. Having an actual hollow all the way through the slug with rifling would probably have increased air resistance compared to having the rifling on the outside, while rifling on the outside would have better ability to apply torque to the projectile. So knowing that rifling on the outside doesn't work well, we can estimate rifling on the inside would do even worse.
- graderjs 5y ago
  Awesome, thanks! Well was worth a try.. Heh