Originally Posted by Gatekeeper
You may find this interesting Shooter Girl.
It may help explain Ballistic coefficient and bullet instability during transonic bullet flight.
Kinda makes my head hurt
from Full Article--->exterior ballistics
At supersonic velocities, the BC of each type of bullet is nearly constant, showing that the G1 drag model is appropriate for these sporting bullets in this velocity range. When bullet velocity falls below about 1600 fps in the transonic velocity range, the BC of each bullet type decreases dramatically. A minimum BC value is reached just above the speed of sound. A dramatic increase in BC value occurs just below the speed of sound. A maximum BC value is reached when the bullet velocity is about 1000 fps, and then the BC value decreases as bullet velocity falls to lower subsonic levels.
Yeah I agree with that. That is because at supersonic speeds the pressure wave in front of the bullet creates somewhat of a dead space directly in front of the bullet, increasing the BC. That does not happen obviously when the bullet is sub sonic. But I don't think that there is a second pressure wave that causes a wobble when it transitions. One thing though. I don't see why 1600 ft/s would be the transonic range, cause the speed of sound at sea level in ideal weather is about 770 mph, or a little over 1100 ft/s. Maybe it will explain further down in the link. Or maybe they are talking at a higher altitude.
Let me finish reading it. Thank you for posting it.
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