That made a huge difference

Finally got some AA1680. (Thanks to my wife, no less) That stuff rules for subsonic 300 BLK. Even with the heavy buffer, it locked back at 11.2 grains, magnum or regular primers. Carbine or pistol. The 150 grain loads worked in either pistol or rifle with H110 loaded to 16.6 to 16.8 grains and regular primers.