It is definitely accuracy issue. With out suppressor 3 shot groups are 1/2 or so at 50 yards, With suppressor 12 - 15 inch groups. I talked to shop where I got it they said need a h3 buffer. I switched it out and no difference
Either an alignment problem of the suppressor on the barrel, or inside the suppressor. Most likely a baffle strike. Holes in the target are most likely not round.
300 Blackout, not just for sub-sonics.