02-05-2020, 04:46 PM
True, faster twist barrel shooting the same bullet gives a higher stability factor.
Not true. Higher BC bullets have a higher stability factor.
Example. A 180gr .308 Sierra GK has a G7 BC average of .242 between 3000-1500 fps.
A 180gr .308 Nosler Accubond has a G7 BC average of .246 between 3000-1500 fps.
Comparing each bullet from the same 1:10 twist barrel the GK has a higher stability factor. Both bullets have the same sectional density. The reason for this is ogive radius expressed in calibers, frictional surface area and boattail length and angle. In this case the lower average BC Bullet has a higher BC as it enters the transonic zone than the higher average BC bullet.
You can clearly see this in Bryan Litz book on Applied Ballistics for long range shooting.
Not true. Higher BC bullets have a higher stability factor.
Example. A 180gr .308 Sierra GK has a G7 BC average of .242 between 3000-1500 fps.
A 180gr .308 Nosler Accubond has a G7 BC average of .246 between 3000-1500 fps.
Comparing each bullet from the same 1:10 twist barrel the GK has a higher stability factor. Both bullets have the same sectional density. The reason for this is ogive radius expressed in calibers, frictional surface area and boattail length and angle. In this case the lower average BC Bullet has a higher BC as it enters the transonic zone than the higher average BC bullet.
You can clearly see this in Bryan Litz book on Applied Ballistics for long range shooting.