As well as in shorter barrel lengths (~8″) the 300BLK is far exceptional for supersonics, at the very least. Long barrel 300BLK is around pointless IMO, you will find other rounds that outperform it handily in exactly the same platform, with same length barrels. Just warning when searching with .300 https://martinvseqb.blog-a-story.com/20253306/the-definitive-guide-to-300-blackout-brass