IF it was possible to get a average size bullet (150-180gr) made like a gameking or partition to break up in mid air, how fast would it have to be going if it would reach a high enough speed?
Back in the 70s I remember seeing the impacted objects of a study on high velocity slugs done by a professor over at Tennessee Tech. If I remember right he hit velocities of around 7000 fps. but only with sabot type rounds made of solid construction. Nothing else would withstand the velocity. Steel targets that were impacted looked like they had liquified and had a hole melted in them. It was interesting stuff.
IIRC it's not the velocity so much as the centripetal force that cause a bullet to "disintegrate". TO clarify velocity does affect the calculation but it is the rotation of the bullet that causes it to come apart. Read this http://www.frfrogspad.com/miscellj.htm#rotating