[Crosshairs10]

Round Ball Questions:

(1) When the center of mass of a spinning projectile is at the same point of its center of pressure, aren't we always then discussing a spherical round ball?


(2) When the center of mass of a spinning projectile is completely aligned with its trajectory and there is no observable gyroscopic effect, aren't we then always discussing a spherical round ball?

(Isn't some gyroscopic spin actually required?)

* I'm of the impression that the longer the projectile, the greater the gyroscopic effect required for stabilization.When there is no elongation, there shouldn't be any gyroscopic spin required.

 

[Mr. C]

In a perfect world, a perfect round ball would need no spin. But...our world is full of little nasty things such as balls aren't perfectly round. Bores are not perfect. Crowns aren't perfect, etc. A slight spin on the round ball helps make the ball behave in a more predictable way and gives a more consistent shot to shot flight. The amount of spin seems to be a matter of personal choice.
I use a 2.5" bore on a canon to experiment with. Often as not, what I observe contradicts what gun books say.

 

[unclenick]

1) No. A straight cylinder, like a solid base full wadcutter, also has its center of mass coincident with its center of pressure.

2) A spinning projectile always has observable gyroscopic effects, so the question is moot.

 

[ranger335v]

Problem with round ball accuracy from smoorh bores is that the bullets do pick up spin in flight. The spin rate and spin axis varies due to surface imperfections acting against the air. Any spin other than precisely at 90 degrees to the bore forces it to drift to the side in totally unpredictable directions and degrees of change.

A ball needs the least possible spin rate to stabalize. A full wad-cutter is next slowest. Projectials must be spun faster as they get longer or accuracy will suffer.

Saying "..Spherical Round Ball.." is redundant.