89blazin, rarely do bullets start keyholing past 500 yards. To date, if they're well stabilized, they'll fly point on with their long axis tangent to the trajectory axis all the way to the target as long as they remain supersonic. They'll all have a microscopic amount of coning due to the tiny amount of unbalance which causes a bit of additional drag but that's only going to cause about a 1% spread in ballistic coefficient, for the most part.
While a bullet's length, shape, diameter and weight are important, so is the rate they're spun at. Each bullet has a narrow range of rpm's that it stabilizes best at. Too fast and their slight unbalance will cause them to jump too far off the muzzle axis; too slow and they'll quickly start wobbling too much and change directions. Which is why a bullet leaving the barrel very fast can have a slower twist than one leaving slower.
US Navy Distinguished Marksman Badge 153
Former USA Palma Team Member
NRA High Power Long Range High Master
NRA Smallbore Prone Master