Oh it is loud on anything shorter then 14.5" AR, and the 556 flashhider end cap helps a bit. Even though it sounds good to me on an 11.5" AR, I still would recommend hearing protection, you can get away with a few rounds or possibly a half a mag, if you REALLY REALLY need to. You're more then welcome to try mine out if you want, I shoot at dead center quite often and at bulleyes.
Thanks, I'll have to take you up on that sometime!