Glavnij kalibr
I don't know much about this brand. What I was able to find is that GK is a project which was started by ex. director of the first russian company which imported swiss watches to Russia. If this is just a brand or has grown into a serious company is unknown to me. But since there are already seven different models in GK collection it seems that project has grown to a company. Where GK watches are assembled is again a mistery to me, almost all models use Miyota quartz movements, RKKA model is for now the only one with automatic (also Miyota) movement.
I have two watches from GK collection. The first one is "Pervij v kosmose", which is a part of Space collection. The second one is Parovoz Josif Stalin, watch which is dedicated to the steam train from 1937.