Thread: Trouble getting 300 Blackout to shoot and cycle subs

An adjustable gas block is used to sort out over gas issues and excessive bolt speed, especially with a suppressor and probably wont sort out your under gas problem with subs. A common problem with a suppressor on a gas impingement system is excessive gas blow back through the chamber and no amount of block adjustment can fix that, combining a properly proportioned suppressor is the answer for that issue.
In this case, as Mikee said, a bigger hole and then regulate with the adjustable block could be the answer.