They can shoot smaller bores in a bigger bore event. As for tubes/inserts, no. There will also only be 1 gun shot at a time. Squads/shooters will not be shooting 2 or 3 guns at a time. That slows everything down. The stands are close enough to make for easy rotations that multiple rounds can be done 1 gun at a time. Keep it simple.
BTW, you can enter events multiple times, but your first round is what counts for score for any awards (Manufacturers Cup is the exception).Manufacturers Cup will be top 5 scores from any manufacturer from the 50 bird prelim events (10,12 & 16) on Friday/Saturday.