400 Km?
The effective range of the S-400 system is reportedly quite impressive (if one is to believe Russian claims), but is limited by the curvature of the earth and can’t penetrate Turkey’s mountainous geography.
So in my opinion 150 km will be the effective range but as mention here Hellenic Air Force will be called upon to locate and destroy S-400s on Turkish soil, that for training crews to conduct low-altitude penetration missions into enemy airspace 24 hours a day.
Please see the attachment.
In my previous comment, I underlined an important point in this regard. The concept of network-centric operations and the place of the S400 in this concept. Of course, the S400 will be subject to range restriction in stand-alone mode and will be an easy target but a S400 that engages in a threat determined in the common air picture within the adavnced network I mentioned will produce a result that you cannot predict in the field and it will have an effective close to the ranges I mentioned.