I found a pound of Lil' Gun powder to try in the Blackout. I like it! I got better accuracy and quieter report with Lil' Gun versus CFE BLK.
Here are a couple of 50yd groups with 8.3gr of Lil' Gun and the 190gr Hornady BTHP:
I did manage to capture a 5-shot group with the Hornady Black 208gr subsonic factory load. Just like I thought, it sucks - 6+ inch group at 50yds!
I'm looking forward to playing with the 220gr bullets I ordered from Midway, today, but the range range won't reopen until January.