300 AAC problem with suppressor

[Trapper539]

So my 300 blackout shoots perfect holes with subsonics but the moment I put on my suppressor the bullets start keyholing really bad and won’t group, that’s both with handloads and store bought ammo, when I’m shooting with the suppressor on any other gun with SuperSonics I’ve never had any issues and still average 0.5” groups at 100 with my 308. What could be my problem?

 

[msgriff]

The first thing to check would be if the suppressor is aligned to the bore of the barrel. Look for baffle/cap strikes, then use an alignment rod.