53.5 is under the starting load recommendations for Berger. At 56.5 I am still 2 grains under max. Did you verify drop and do a calculation to back up the chrony? My guess is 2750 and 60 inches drop from a 200 yard zero.

My load throws 140 Bergers at 2970 to 3000 depending elevation and temp. Speed is calculated from chrony, from drop, and from ballistics solutions from 200 to 1660 yards.