From what information I could find the Barnes 300 AAC Blackout 120 Grain, Jacketed Hollow Point ammo is supersonic and the ballistic information for the ammo is from testing with a 16" barrel. So in terms of stability with a 7.5-10.5" barrel and suppressor compatibility I recommend contacting Barnes Bullets for that information.
i shoot this ammo in a 8" barrel with great results....i don't use a suppressor....my grand daughters shoot some sub sonic ammo...might mention i keep my shooting 150 yards on down....300 blk is a pleasure to shoot with great results on hogs and deer...placement of the bullet is important but that is necessary with any caliber
Yes i use in my honey badger suppressed or unsuppressed very dood stuff
Sounds like you’re looking for good subsonic ammo for that platform. Look at discreteballistics