Quote:
Originally Posted by Norm Peterson
Is there some upper end to how fast a bullet should be spinning, and wouldn't there be some dependency on muzzle velocity?
Unless I've missed something really important, 1 in 9 for a .223 Remington sounds like well over 200,000 rpm.
Norm
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Stability, especially at LR ,is of course dependent on velocity. When conditions are just right, you can see the air disruption, or "trace" of the slug as it passes through the air. Follow it out to the point the slug goes unstable and you can actually see it veer off. It's very cool to see.
Lots of shooters will build a rifle to shoot heavy/long slugs then want to shoot the very light slugs for that caliber as well. Many will say the bullet is "over stabilized" whatever that means? I have a 6mm with a 1 in 8" twist and it will shoot as light as 80 gr bullets at well in excess of 3200 fps and they ALL seem to make it to the paper.
BUT...to muddy the water...I have also seen very light, very frangible varmint bullets in my .220 Swift, with a 1 in 9" HART barrel....NOT make it to the target! Then again...very thinly jacketed slugs. A slight bit of out of balance and they are dust.
Go to the Berger bullet site and they have a chart with the twist rates suggested for their various bullets.