I have been doing an lot of work with Blackout over the last few months. Mainly suppressed subsonic loads, 995FPS with 220Grainers in full and semi auto as well as straight pull. The semi's & full have been short 9'' barrels with pistol gas systems and its a battle between getting the right chamber pressure to cycle the action with fast burning powders as opposed to the slow dirty stuff. No such problems with straight pulls of course. We have developed a more refined chamber reamer and its delivering very promising accuracy with these slow heavy bullets.