I have said it before and I will say it again. This is really a golden age for AK shooters. There are more options than ever when it comes to making that reliable old warhorse m0re efficient. Muzzle brakes, in particular, have received a lot of development lately.
SLR Riflesworks is now offering their SR47 Series Muzzle Brake for the AK. This is a very compact brake with a single port design. It has just a 1.2″ overall length which is nice if you are trying to keep length to a minimum. This brake is symmetrical and it has two indexing points spaced 180 degrees apart which increases the chances of a snug fit. The SR47 Series Muzzle Brake is optimized for the 7.62×39 but should also work for you 5.45 shooters as well. It has a 14x1L thread pattern.