But all bullets are down to 1150 fps when starting to go subsonic.
No matter what they were started at.

They have the most disruption(wobble), I understand at the point
of going subsonic and if started like a lot of blunt shotgun slugs
at 1300 they are going through that change at 70-100yds.
After that they settle down and don't wobble so much, but 12ga slug
trajectory, at 1300 slow start, is terrible so most guys don't use them at longer ranges.
Hence the search for speed so they stay supersonic out to 200 yds.Ed