When the gun doubles, it is considered a gun malfunction based on the NSCA NSSA 2017 Rule Book (VII-H-1-a).
The shooter shall be allowed a combined total of three (3) malfunctions
per day, per event attributed to either the shooter's gun or ammunition.
Targets not attempted on the three (3) allowed
malfunctions shall be treated as NO BIRDS.
1. Gun Malfunctions
a. Gun malfunctions include the situations where (a) the
gun will not fire either barrel (The shooter must keep
the gun pointed downrange and present it to the field
judge who must verify that the condition persists as an
inoperable gun. If the gun subsequently fires, it will be
deemed a shooter malfunction.); (b) the gun had a true
simultaneous discharge (gun doubles); (c) the gun fan
fires (second barrel discharges without shooter action);
and (d) a semi-automatic shotgun fails to eject the shot
shell from the first shot and a second shot is required.
In the event of a gun malfunction the first target is considered a NO BIRD, so the pair is repeated.