Larry
You said: The evidence so far still clearly points to RPM. Remember; same pressure, same velocity, (both of which evens out any difference in "rotational friction") much larger proportional change in accuracy with the 10" twist vs the 12 and 14" twist. The 12" twist also has a proportionally lager change in accuracy than the 14" twist. The only difference between them is RPM. Regardless of the straws we try to grasp the evidence so far is pointing in one direction only, RPM.
To that I say that this is what you say, not all of us. You are the great Albert Einstein, everyone has to prove him wrong. Is this a plan of yours having other find the real reason why there is a difference between rifling twists at higher rpm/velocity?
Yes I have shot the many different bullets out of the faster 22 bores. If I didn't have the rifle I was fortunate enough to have friends that did. We did not come to the same conclusion as have you. What I have found about the tags in bullet boxes is that most have a velocity limitation not a rifling twist limitation. Before you reply to that let me say that does not include the twist limitation because of the heavy weight for bore such as the newer 22 caliber bullets that require the 7, 8, and 9 rifling twists. That is why I found runfiverun's post interesting.
I have thought about Bass's deep rifling twist ideas. I have gone back through old post material and one that caught my attention was when there was much posting about the M95 Steyr 8x56R. It was mentioned in those old post about how deep the rifling is in that rifle. As I recall some of the members were were getting very decent shooting with this caliber and Bass mentioned the deeper rifling in that caliber. I like to agree with him in that area.
Ralf