As well as in shorter barrel lengths (~8″) the 300BLK is much superior for supersonics, at the very least. Long barrel 300BLK is in the vicinity of pointless IMO, you will discover other rounds that outperform it handily in precisely the same System, with very same length barrels. You'll need https://israelugypj.tribunablog.com/5-essential-elements-for-300-blackout-brass-52168670