The FSC556 JUST works soo well.
I have tested a bunch of comps on my uppers, and the FSC556 works best IMO, and it helps reduce flash signature also.
Heck if you WANT a nice and big flash for good pictures, get a DNTC brake (previous version of the FSC556, but it makes for a good 2-3foot flame out of the rifle is the light is right.

, but makes for almost ZERO muzzlejump during rapidfire.