Easy -- a Micor Flash Arrestor. They are the best thing I have seen primarily for accuracy. The slots are matched to the twist of the rifleing matching exhaust gases as they exit the barrel. Guns WITHOUT muzzle devices are always a little more accurate than with one. But not in the case of the Micors -- it is like they are not there yet they provide more flash suppression and the same braking as the GI ones. Even the titanium ones (yes, titanium!) are less than $100.
I first saw them in a Jeff-whatever-the-guys-name-is-with-the-screwy-beard review. Now I use them exclusively. Even pulled a YHM Phantom off of one to do it -- big improvement.