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.