Re: which muzzle brake
I've not yet purchased a mic for use with my ComTacs, but I've done a bit of research on Peltor's site as well as a few of the tactical equipment vendors that sell systems based on Peltor products. Just search with Google on Peltor Comtac - you'll get a number of mic options that'll do what you want...
STL. Principal Consultant and Managing Partner - Association of Bifurcated Tangential Ballistic Apologists, LLP.