so, i caught the short barreled 300blk bug and i just cant shake it. its so bad that i have no other option but to run a suppressor so that its not so painful on my ears! all subsonic data or info i can find is atleast a couple years old and i am having a hard time finding out what people are perscribing their subsonic rounds on the reloading bench. ive heard 1680 is the ticket to reliable subsonic cycling in an AR type rifle but as hard as it is to come by i am curious as to what else will work?? 10" barrel Pistol Gas M16 carrier Carbine buffer for now for all of you with this same or similar bug...cheers!