Will Geco 124 9mm stay subsonic?

[Nicu757]

Ok so I messed up and bought a case of 124 grain Geco 9mm. Great ammo!! But from my 5.5 inch AR don't think it will not have the crack or boom. Want to trade it or sell it so don't want to try any or buy more. Thoughts???

 

[Nicu757]

Sold thanks. Would still like input if it would stay sub sonic

 

[M67]

A quick search found 124gr Geco at 1180FPS. Hard telling barrel length but if I had to guess, it would be super sonic out of a 5.5" barrel