Hornady® 300 Blackout Subsonic Ammunition is designed for accuracy and performance below the speed of sound. The new 190 gr Sub-X™ (Subsonic - eXpanding) bullet features a lead core. Long grooves in its gilding metal jacket combine with the bullet’s flat profile and the patented Flex Tip® insert within its hollowpoint cavity to help it expand reliably at low velocities.
Performance of the Hornady® 300 Blackout Subsonic load meets or exceeds FBI Protocol terminal ballistic test requirements.
I have used this round a couple years now and have cycled without issue from AR and bolt guns. Harvested 4 whitetails that I can recall from 50 to 90 yards. Have yet to see one pass through a deer but the farthest I've had one run once shot is 30 yards. So I would say it does pretty dang good. I see a lot of bad reviews but I've had good luck with them with well placed shots. I can see where a issue could come up if you don't place your rounds where they should go. But that's the same with all ammo.