As well as in shorter barrel lengths (~8″) the 300BLK is much remarkable for supersonics, at the least. Extended barrel 300BLK is in the vicinity of pointless IMO, you will find other rounds that outperform it handily in the identical System, with identical duration barrels. Stick to published information only, https://300aacbrass85173.madmouseblog.com/19720793/300-blackout-reloading-can-be-fun-for-anyone