If one powder and projectile mostly for subsonic masses turns out to operate for .300 Blackout that might be great. If it turned out to that CFE 223 could fill that part that could be the What's even better worlds. Among two resources I discover indispensible, not including Those people https://300-blackout-projectiles15317.timeblog.net/73482312/the-ultimate-guide-to-300-aac-brass