The UK's Finest Independent Forum for Shooters and Gun Owners. Est 2010.

How?

John25 wrote:How?

clapclap

I remember.

The Greenhill Formula is a simplified method for determining mathematically the amount of spin necessary to stabilize a bullet.
I prefer to use Gyroscopic Stability (GS) = the spin rate (in radians per second, squared) times the polar moment of inertia, squared, divided by the pitching moment coefficient derivative per sine of the angle of attack times the transverse moment of inertia times the air density times the velocity squared.. For the bullet to be stable, GS > 1.0.
This is actually a short version as the pitching moment coefficient component is a complicated calculation that derives the center of gravity and the center of reverse air pressure. The equation is basically calculating the linear difference between the center of gravity and the center of reverse air pressure on the nose of the bullet. The greater the difference, the greater the spin required to keep the bullet pointed nose forward.

Do you think then, that your method is more suited for the higher muzzle velocities?

DOGGER2UK wrote:The Greenhill Formula is a simplified method for determining mathematically the amount of spin necessary to stabilize a bullet.
I prefer to use Gyroscopic Stability (GS) = the spin rate (in radians per second, squared) times the polar moment of inertia, squared, divided by the pitching moment coefficient derivative per sine of the angle of attack times the transverse moment of inertia times the air density times the velocity squared.. For the bullet to be stable, GS > 1.0.
This is actually a short version as the pitching moment coefficient component is a complicated calculation that derives the center of gravity and the center of reverse air pressure. The equation is basically calculating the linear difference between the center of gravity and the center of reverse air pressure on the nose of the bullet. The greater the difference, the greater the spin required to keep the bullet pointed nose forward.

I just load em and shoot em , if they go through the target sidways i try something else ?

Works for me :goodjob:

pe4king wrote:Works for me :goodjob:

Do you use his original formula or one of the modified ones?

Brilliant Royal Artillery Officer I believe

John25 wrote:

pe4king wrote:Works for me :goodjob:

Do you use his original formula or one of the modified ones?

I use the "use a bigger hammer" formula