As well as in shorter barrel lengths (~8″) the 300BLK is much top-quality for supersonics, at least. Long barrel 300BLK is in the vicinity of pointless IMO, you can find other rounds that outperform it handily in precisely the same platform, with same duration barrels. There are numerous 300 Blackout https://300-blackout-cases21740.jts-blog.com/37684412/top-brass-300-blackout-secrets