I shot my 300 win mag at 100 yds. 2 -2.5 inch groups were consistent. Yes, I tried 4 different types, bullet weights and brands of ammo. Mounted 3 different scopes including buying a Leupold vx3. No change. With the ammunition($40 plus per box) and cost of the new optic, I could have just bought a remington or winchester. Sent this gun back to cva almost a month ago. We'll see what they say. It's a gamble to drop 600 on this rifle. Hopefully, they make it right. Never had a bad muzzleloader from cva.. for what thats worth.
Unless you handload, you will have a hard time finding subsonic .300WM ammo. However, a suppressor will still significantly reduce the felt recoil and tame a lot of the report of a .300WM (of course, the bullet going supersonic will still make a good amount of noise!). Also, since suppressor manufacturers make them bullet diameter specific, you can buy a 30 caliber suppressor for your subsonic .308 or .300 blackout loads and move it to your .300WM!