I was a relatively early adopter in the blackout. It seems at that time there were not high quality expanding bullets available in weights that could be loaded to subsonic. I read many reviews on the Barnes Tac Tx 110 gr and loaded a few hundred rounds with them. They are known to perform well but there are many bullets suitable for subsonic that are also available now.I’ve never understood shooting supersonic rounds in a blackout. Significantly better options.
I like the subs though.