Hi James, unless you are going to run it suppressed, there's no purpose in running subsonic uncanned. The backpressure will not be enough to run reliably (if at all), and the accuracy will will also suffer.
.300blk subsonic is a fun round to shoot suppressed and it's the only way to shoot it reliably.
The twist rate is 1:10
Stay safe & have a great day!

Hi James and welcome. The barrel twist rate is 1 in 10 inches. Subsonic ammunition will not be an issue. Cheers, stay safe and enjoy!

It is doubtful that It will function however the only real way to know is to try some in your gun It may work in one ATI Alpha Max and not another Twist is 1:10

1 in 10 yes it can handle subs