It does not matter if you go brake, FH or thread protector. On the Grendel forum you see completed Grendel's with everything. I think most do the mb since that's what's required due to state law. The best muzzle break imo for the Grendel is the one made by precision firearms. The worst flash hider imo is the AAC 51t, because it makes a ping noise after each shot.
Good luck in deciding
