subsonic ammo

I recently purchased some Subsonic 300 Blackout ammo for my AR but it doesn't cycle correctly and jams the gun. My understanding is that the subsonic rounds are made for a suppressed AR. Do these subsonic rounds cycle correctly in a suppressed AR? or is the subsonic round just not powerful...

So I'm thinking about suppressors and subsonic ammo. I feel that a bullet is a bullet and if it hits something it's going down or it's not going far. I don't see concern over a lower muzzle velocity within a reasonable distance. I'm posting this because a lot of sites and people say that...