The scorer will measure the main beams from the burr to where they break. The G3s will be measured from where they come off of the main beam.
Haven't you ever seen a buck where his main beams turn up radically at the tips?
Yes, and they are still the mainbeams. It usually happens after the G3s. This buck's main beams broke after the G3s. One a little more than the other.
Are you saying that the scorer would take the tape from the burr, and when he hits the G3s, makes a 90 degree upward turn and calls that the end of the main beam? Why wouldn't he run the tape until he runs out of main beam to measure?