Sources in the military or defense industry tell Russian press that the first ejection test of the Sarmat missile did take place in Plesetsk. Normally, MK is not the most reliable source, but this time the information appears to be correct - sources on the other side also say that the test did happen.
The MK report leaves the impression that the test took place in the last few days of this year, but the test apparently took place in early December. Which is interesting - a few days ago Rogozin had a chance to comment on the progress of the Sarmat program and he refused to say anything. In any event, the program is clearly behind the schedule and my take is that the chances of Sarmat being deployed in 2020 are extremely slim.
One detail in the MK report caught eye of a few observers - the missile reportedly flew "several tens of kilometers" before landing "within the test site." This is a bit too far for an ejection test. It's quite possible that the reporter mixed up meters and kilometers. Or the launch involved a limited test of the first stage engines. A mix-up seems a safer bet, but a test of the engines is possible as well.
The bmpd blog of the CAST Center says that the test did not involve the first stage engine. According to their information, two more ejection tests will take place in the first half of 2018.
Comments
I bet these tests happened from the re-constructed site at Serebryanka
http://up.picr.de/31375697xg.jpg