Originally Posted by goodgrouper
It matters more that the yaw is reduced as much as possible as fast as possible and that comes from twist rate or distance covered by one revolution and also a host of other things.
This is true.
Stabilization follows displacement per turn, NOT turns per time.
In your example above I can demonstrate why anyone should forget RPMs -forever.
140vld at 3000fps from a 8.5:1 barrel would have an Sg~1.40 under ICAO conditions. This happens to be 254Krpms.
Same bullet at 3300fps would be spinning 254Krpms from a 9.4:1 barrel. But under same conditions this twist rate would produce an Sg of only ~1.15
At 3600fps, 254Krpm would come from a 10.2:1 barrel. this is the point where the bullet performance completely sucks though, as Sg would be ~1.00 at ICAO.
So stability here is greatly affected regardless of rpms..
It is DISPLACEMENT PER TURN that has by far the largest influence on bullet stability.
Also, another factor not accounted for from an rpm perspective, is air density. This can wildly affect stability as well. It is the second largest influence, followed by muzzle release quality, and then dynamic design issues.
Any connection with RPMs is pure coincidental.