So I have found 2 types of picatinny rails for CZ550: by CZ itself and by EGW.
I tried both, and was disappointed to both of them. Particularly to EGW, I can't make a snug fix between EGW rail and CZ dovetail.
Recently I come across with Recknagel Picatinny Rail for CZ 550. Does anybody have experience with it?