Which Powders Are Best For Subsonics???

[sgms18]

I am geting ready to start loading subsonics for my 300-221 AR that I just finished and am wondering what powders will give me the best results? I will be using 180 to 240 grain bullets through a 16in bbl, and it will have a suppressor on it(if that makes any diff). Also any good load data would be greatly app!!!:uzi2:

[Colohunter]

I like Acurate Arms 1680. I haven't tried a lot of powders, but 1680 has worked to cycle subsonic, down to 150 grains for me in my M1S upper.

[kdiver58]

^^^^^^^

What he said ... I'm down to 11.5 grains of it behind a 220 grain SMK and it cycles with a can on.