The data provided by Backfire shows the 27 Nosler has the most drop and dead last or second to last out of 11 different rounds...Using Ron Spomer's data, for "normal" handloads or factory, the 6.5-300 is second to the 240 Weatherby at 300, #1 at 500 yards and second to the 27 Nosler at 1000.
So it retains "flatness" a long way.
Depends on bullet but it's pretty solid I haven't started the database but it will be hard to top.
@ 10:50 in the video...