Thanks to all who commented on this issue. The aircraft had just had its annual and this was its first flight and also the first time that a mag drop had been experienced, hence the concern! The company that did the check have looked at it again this week. The static ground run produced just below 2200 rpm which, according to them, is correct. I think an optcal rev. counter was used, as they quoted a resolution better than 100 rpm The performance in the air, i.e., airspeed /rpm relationship was as previously experienced, about 100 knots at 2225rpm at 2-3000'.
Hopefully all is well....
