We all did this and most of the calculators were close to dead on.
Then, we decided to try for 400 yards. I dialed up 17 mils, which is all my scope travel and held 3.5 mils for about 20.5 mils total.
The wind was swirling, we were in between forest in a narrow corridor of a lane and reading the value was tough.
400 is a long way for a subsonic rimfire.