Long story short: I just ordered an EGW Picatinny Rail for my CZ 550 .375 H&H. (Not a lot of rail options for CZ 550 Magnums.) Anyhow, my CZ 550 is LH and the EGW rail is for a RH gun. (Recoil lug is on the other side and the rail attaches to the lug.) So, if you need / want a Picatinny rail for your CZ 550, send me a PM. I will let it go cheap ... real cheap. Brand new and obviously never used/mounted.