Greetings, I recently submitted my form 4 for a Gemtech Sandstorm TI 7.62 suppressor. Now the fun starts. I am starting the process of developing a subsonic round that works well in my AR-10. I have 9 months while the ATF processes the paperwork so I'm not in a big hurry (might take me that long to find a 1lb of Trailboss powder). Here is some of my concerns, if anyone has previous history with this I would welcome the help. I want a round that has enough powder to cycle my AR, but not enough to create a sonic crack. I have read trailboss is the preferred powder, I should drill my flash holes to 9/64" and use magnum primers to ensure all the powder is ignited. I'm also very concerned about bullet tumble when it leaves my barrel into the silencer. I selected Hornady round nose 150gr bullets and hope to have this figured out before I screw on the silencer later in the year. Lastly, accuracy. I kind of feel I want to have my cake and eat it too after reading a lot of posts. Anyone have tips for a new-be to the world of silent shooting? Thanks!