6-year-old thread, so the original participants are mostly no longer looking.
For historical reference, the 10" 30 caliber twist was used initially in the 30-40 Krag for stabilizing 220 grain round nose bullets. The military just kept that 10" twist until the M14 was developed. It is more spin than is necessary for short bullets. However, most bullets of modern manufacture are better balanced (have better mass symmetry) than they did a hundred years ago, so spinning too fast no longer tends to lob them laterally off the trajectory and make them wobble badly in flight the way it once did. The main thing you have to watch out for with too much spin for a short, light bullet is core stripping, where the angular (rotational) acceleration gets so great the core slips inside the jacket, which deteriorates group size rather significantly. Light solids don't have that problem, though.