Loss of accuracy is not the problem with overstabilization, which has been thoroughly proved by classic (but simple) experiments and extensive field observations well beyond anything that Ross Seyfried is likely to have done to study the concept.
Overly stable bullets don't tip nose-down as their trajectories arc over and start dropping. This means that as it travels, the overly stable bullet flies less and less point-on, more and more nearly sideways. (I'll look to see whether I can resurrect and -- later -- post a couple of drawings that illustrate adequate and excessive stabilization.)
At extreme range, it falls to a horizontal surface with its point still higher than its tail, at very nearly the same nose-up angle that it left the muzzle. It may still be grouping well, but that's another matter altogether.
What matters is that the overstabilized bullet (a) loses velocity faster and (b) consequently has a much shorter practical range than the same bullet just barely (but adequately) stabilized.
IOW, the field-derived de facto ballistic coefficient of the overly stable bullet is lower than it would be if the bullet were only border-line stable -- just stable enough (and just nearly unstable enough) to fly its entire trajectory point-on
Thanks for posting your reminder that shooters, readers, writers, and editors need a better understanding of ballistics!
