There are several good threads on doing subsonic ammo for the 6.5 Grendel. I suggest you use the google custom search on. Cast Subsonic
https://cse.google.com/cse?cx=0163689474...cu1o&hl=en
I doubt you can get a trailboss load to cycle in a AR-15 but I never have tried to do subsonics. My suspicion is there wouldn’t be enough gas or pressure to cycle an AR-15. There is a video of a person shooting subsonic ammo through a suppressor with a 6.5 Grendel AR-15 and it functioned 100% in the second video.
https://www.youtube.com/watch?v=if0EgLcxTHw
https://www.youtube.com/watch?v=fqWQSnQ0mzI
https://cse.google.com/cse?cx=0163689474...cu1o&hl=en
I doubt you can get a trailboss load to cycle in a AR-15 but I never have tried to do subsonics. My suspicion is there wouldn’t be enough gas or pressure to cycle an AR-15. There is a video of a person shooting subsonic ammo through a suppressor with a 6.5 Grendel AR-15 and it functioned 100% in the second video.
https://www.youtube.com/watch?v=if0EgLcxTHw
https://www.youtube.com/watch?v=fqWQSnQ0mzI