Subsonic 300 Blackout Powder Options

I am working on a low velocity/subsobsonic load for a 230 grain cast boolit in a 300 Blackout on an AR-15 frame. I have, based on thread search, tried 9.5 grains of H-110 and the gun runs like a charm. Now for the problem, I am running out of H-110 powder. Result indicates that Accurate 1680 is a very good choice for this round. Recognizing that I may not be able to find Accurate 1680 anytime soon, I need to find a powder that will work.

There is about 10 steps between the burn rates of H-110 and Accurate 1680. Why can't I develop a load with ANY of the powders in that range? I have seen some posts that indicate a powder as slow as Reloader 7 can be used.

Please tell me if this makes sense and where I may be going wrong.

I've used lil gun, h110 & 1680. All work fine. Seen reports of 5744, 2400 and rl7 all being used successfully in an AR. In my bolt gun, unique works quite well.

there is data for I4227 and I4198 and subsonic bullets on the Hodgdon site. The data is for jacketed bullets. I have only used H110 with cast lead in my AR platform 300 BO.

BB

+1 for Lil Gun.