And in shorter barrel lengths (~8″) the 300BLK is much exceptional for supersonics, at least. Long barrel 300BLK is around pointless IMO, you will find other rounds that outperform it handily in exactly the same System, with same duration barrels. Of importance, the non-adjustable fuel block resides in the pistol https://andretbinv.webbuzzfeed.com/38897616/getting-my-300-blackout-cases-to-work